DAY – 15 : Insta 75 Days Revision Plan-2025 : ENVIRONMENT & ECOLOGY

Read about Insights IAS INSTA 75 Days Revision Plan for UPSC Civil Services Prelims – 2025 [ HERE ] :

DOWNLOAD THE INSTA 75 DAYS REVISION TIMETABLE(GS) [HERE] :

DOWNLOAD THE INSTA 75 DAYS REVISION TIMETABLE(CSAT) [HERE] :

Download MITRA booklet (My Insta Tests Revision and Assessment) – It’s for to track your daily progress while following Insta 75 Days plan. [ CLICK HERE ] :

#### Quiz-summary

0 of 30 questions completed

Questions:

#### Information

Wish you Good Luck! 🙂

You have already completed the quiz before. Hence you can not start it again.

Quiz is loading...

You must sign in or sign up to start the quiz.

You have to finish following quiz, to start this quiz:

0 of 30 questions answered correctly

Your time:

Time has elapsed

You have reached 0 of 0 points, (0)

Average score |

Your score |

#### Categories

• Not categorized 0%

Pos. | Name | Entered on | Points | Result

Table is loading

No data available

| | | |

• Question 1 of 30 1. Question 1 points The Blue Carbon Initiative is jointly led by: (a) UNEP, WWF, and Greenpeace (b) Conservation International, IUCN, and IOC-UNESCO (c) FAO, UNDP, and World Bank (d) IMO, UNFCCC, and IPCC Correct Solution: B The Blue Carbon Initiative is a coordinated, global program focused on conserving and restoring coastal ecosystems for their role in climate change mitigation. It is jointly led by the Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO), the International Union for Conservation of Nature (IUCN), and Conservation International. Hence, option (b) is correct. Incorrect Solution: B The Blue Carbon Initiative is a coordinated, global program focused on conserving and restoring coastal ecosystems for their role in climate change mitigation. It is jointly led by the Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO), the International Union for Conservation of Nature (IUCN), and Conservation International. Hence, option (b) is correct.

#### 1. Question

The Blue Carbon Initiative is jointly led by:

• (a) UNEP, WWF, and Greenpeace

• (b) Conservation International, IUCN, and IOC-UNESCO

• (c) FAO, UNDP, and World Bank

• (d) IMO, UNFCCC, and IPCC

Solution: B

The Blue Carbon Initiative is a coordinated, global program focused on conserving and restoring coastal ecosystems for their role in climate change mitigation. It is jointly led by the Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO), the International Union for Conservation of Nature (IUCN), and Conservation International.

Hence, option (b) is correct.

Solution: B

Hence, option (b) is correct.

• Question 2 of 30 2. Question 1 points The “Edge Effect” in fragmented ecosystems refers to: (a) Increased vulnerability of edge habitats to invasive species due to altered environmental conditions (b) Decreased genetic diversity in edge populations due to reduced gene flow (c) Modified environmental conditions at habitat boundaries that affect species composition and abundance (d) The tendency of endangered species to occupy peripheral habitats when core habitats are disturbed Correct Solution: C Edge effects refer to the changes in population or community structures that occur at the boundary of two habitats. These effects are particularly pronounced in fragmented ecosystems, where habitat patches are separated by human-modified landscapes or natural barriers. Increased Biodiversity at Habitat Boundaries: Edges often support species from both adjacent ecosystems, leading to an overlap of species and potentially higher biodiversity in the transition zone. This is known as the edge effect, where the overlapping area can support species from both ecosystems plus additional species unique to the edge environment Modified Environmental Conditions: The conditions at habitat boundaries, such as increased light, temperature, and wind exposure, differ significantly from the interior of ecosystems. These altered conditions can favour certain species, particularly those that are shade-intolerant or can tolerate harsher environments, leading to changes in species composition and abundance. Endangered Species and Peripheral Habitats: Endangered species might occupy peripheral habitats when core habitats are disturbed, but this is not directly related to the edge effect. Instead, it’s a consequence of habitat fragmentation and loss of core habitat Hence, option (c) is correct. Incorrect Solution: C Edge effects refer to the changes in population or community structures that occur at the boundary of two habitats. These effects are particularly pronounced in fragmented ecosystems, where habitat patches are separated by human-modified landscapes or natural barriers. Increased Biodiversity at Habitat Boundaries: Edges often support species from both adjacent ecosystems, leading to an overlap of species and potentially higher biodiversity in the transition zone. This is known as the edge effect, where the overlapping area can support species from both ecosystems plus additional species unique to the edge environment Modified Environmental Conditions: The conditions at habitat boundaries, such as increased light, temperature, and wind exposure, differ significantly from the interior of ecosystems. These altered conditions can favour certain species, particularly those that are shade-intolerant or can tolerate harsher environments, leading to changes in species composition and abundance. Endangered Species and Peripheral Habitats: Endangered species might occupy peripheral habitats when core habitats are disturbed, but this is not directly related to the edge effect. Instead, it’s a consequence of habitat fragmentation and loss of core habitat Hence, option (c) is correct.

#### 2. Question

The “Edge Effect” in fragmented ecosystems refers to:

• (a) Increased vulnerability of edge habitats to invasive species due to altered environmental conditions

• (b) Decreased genetic diversity in edge populations due to reduced gene flow

• (c) Modified environmental conditions at habitat boundaries that affect species composition and abundance

• (d) The tendency of endangered species to occupy peripheral habitats when core habitats are disturbed

Solution: C

Edge effects refer to the changes in population or community structures that occur at the boundary of two habitats. These effects are particularly pronounced in fragmented ecosystems, where habitat patches are separated by human-modified landscapes or natural barriers.

• Increased Biodiversity at Habitat Boundaries: Edges often support species from both adjacent ecosystems, leading to an overlap of species and potentially higher biodiversity in the transition zone. This is known as the edge effect, where the overlapping area can support species from both ecosystems plus additional species unique to the edge environment

• Modified Environmental Conditions: The conditions at habitat boundaries, such as increased light, temperature, and wind exposure, differ significantly from the interior of ecosystems. These altered conditions can favour certain species, particularly those that are shade-intolerant or can tolerate harsher environments, leading to changes in species composition and abundance.

• Endangered Species and Peripheral Habitats: Endangered species might occupy peripheral habitats when core habitats are disturbed, but this is not directly related to the edge effect. Instead, it’s a consequence of habitat fragmentation and loss of core habitat

Hence, option (c) is correct.

Solution: C

Hence, option (c) is correct.

• Question 3 of 30 3. Question 1 points Consider the following pairs: Adaptation Function 1. Pneumatophores Gas exchange in waterlogged soils 2. Cryptobiosis Surviving extreme drought conditions 3. Counter-current heat exchange Maintaining body temperature in cold environments 4. Bioluminescence Attracting prey in deep-sea environments How many pairs given above is/are correctly matched? (a) Only one pair (b) Only two pairs (c) Only three pairs (d) All four pairs Correct Solution: D All pairs are correctly matched. Pneumatophores: These are specialized roots found in mangroves that facilitate gas exchange in waterlogged soils. Mangroves grow in intertidal zones where the soil is often anaerobic due to waterlogging. Pneumatophores extend above the water level, allowing the plant to access atmospheric oxygen for its roots submerged in water Cryptobiosis: This is a survival strategy where organisms, like nematodes and tardigrades, enter a state of suspended animation to survive extreme drought conditions. During cryptobiosis, metabolic activity is greatly reduced or halted, and the organism can endure desiccation, freezing, and anoxia Counter-current heat exchange: This mechanism is used by organisms to maintain body temperature in cold environments. It involves the close positioning of arteries and veins, allowing heat to be transferred from the warm arterial blood to the cooler venous blood, thereby reducing heat loss to the environment. Bioluminescence: This is the production and emission of light by living organisms through a chemical reaction. In the deep sea, bioluminescence serves various functions, including attracting prey. Deep-sea anglerfish, for example, use a bioluminescent lure to attract curious prey in the vast, dark expanse of the deep ocean licitly outlines the appointment process for several key constitutional functionaries to ensure transparency and maintain the balance of power. Attorney General of India: Article 76(1) of the Constitution specifically mentions that the President shall appoint a person qualified to be a Supreme Court judge as the Attorney General of India. Comptroller and Auditor General of India: Article 148(1) clearly states that the CAG shall be appointed by the President by warrant under his hand and seal Solicitor General of India: The Constitution does not explicitly mention the appointment of the Solicitor General. This position is not a constitutional post but a statutory one. Article 316(1) of the Constitution specifies that the Chairman and other members of the Union Public Service Commission shall be appointed by the President. Hence, option (c) is correct. Incorrect Solution: D All pairs are correctly matched. Pneumatophores: These are specialized roots found in mangroves that facilitate gas exchange in waterlogged soils. Mangroves grow in intertidal zones where the soil is often anaerobic due to waterlogging. Pneumatophores extend above the water level, allowing the plant to access atmospheric oxygen for its roots submerged in water Cryptobiosis: This is a survival strategy where organisms, like nematodes and tardigrades, enter a state of suspended animation to survive extreme drought conditions. During cryptobiosis, metabolic activity is greatly reduced or halted, and the organism can endure desiccation, freezing, and anoxia Counter-current heat exchange: This mechanism is used by organisms to maintain body temperature in cold environments. It involves the close positioning of arteries and veins, allowing heat to be transferred from the warm arterial blood to the cooler venous blood, thereby reducing heat loss to the environment. Bioluminescence: This is the production and emission of light by living organisms through a chemical reaction. In the deep sea, bioluminescence serves various functions, including attracting prey. Deep-sea anglerfish, for example, use a bioluminescent lure to attract curious prey in the vast, dark expanse of the deep ocean

#### 3. Question

Consider the following pairs:

Adaptation | Function

1.Pneumatophores | Gas exchange in waterlogged soils
2.Cryptobiosis | Surviving extreme drought conditions
3.Counter-current heat exchange | Maintaining body temperature in cold environments
4.Bioluminescence | Attracting prey in deep-sea environments

How many pairs given above is/are correctly matched?

• (a) Only one pair

• (b) Only two pairs

• (c) Only three pairs

• (d) All four pairs

Solution: D

All pairs are correctly matched.

Pneumatophores: These are specialized roots found in mangroves that facilitate gas exchange in waterlogged soils. Mangroves grow in intertidal zones where the soil is often anaerobic due to waterlogging. Pneumatophores extend above the water level, allowing the plant to access atmospheric oxygen for its roots submerged in water

Cryptobiosis: This is a survival strategy where organisms, like nematodes and tardigrades, enter a state of suspended animation to survive extreme drought conditions. During cryptobiosis, metabolic activity is greatly reduced or halted, and the organism can endure desiccation, freezing, and anoxia

Counter-current heat exchange: This mechanism is used by organisms to maintain body temperature in cold environments. It involves the close positioning of arteries and veins, allowing heat to be transferred from the warm arterial blood to the cooler venous blood, thereby reducing heat loss to the environment.

Bioluminescence: This is the production and emission of light by living organisms through a chemical reaction. In the deep sea, bioluminescence serves various functions, including attracting prey. Deep-sea anglerfish, for example, use a bioluminescent lure to attract curious prey in the vast, dark expanse of the deep ocean

licitly outlines the appointment process for several key constitutional functionaries to ensure transparency and maintain the balance of power.

Attorney General of India: Article 76(1) of the Constitution specifically mentions that the President shall appoint a person qualified to be a Supreme Court judge as the Attorney General of India.

Comptroller and Auditor General of India: Article 148(1) clearly states that the CAG shall be appointed by the President by warrant under his hand and seal

Solicitor General of India: The Constitution does not explicitly mention the appointment of the Solicitor General. This position is not a constitutional post but a statutory one.

Article 316(1) of the Constitution specifies that the Chairman and other members of the Union Public Service Commission shall be appointed by the President.

Hence, option (c) is correct.

Solution: D

All pairs are correctly matched.

• Question 4 of 30 4. Question 1 points Consider the following statements about energy flow in ecosystems: According to Lindeman’s efficiency, only about 10% of energy is transferred between trophic levels The detritus food chain is very efficient in recycling nutrients and utilizing the energy stored in dead organic matter The maximum energy in any food chain is concentrated at the producer level How many of the statements given above are correct? (a) Only one (b) Only two (c) All three (d) None Correct Solution: C Lindeman’s trophic efficiency rule, also known as the 10% law, states that only about 10% of the energy from one trophic level is transferred to the next, with the remaining 90% lost as heat or used for metabolic processes Hence, statement 1 is correct. Detritus food chain begins with dead organic matter (detritus), which is consumed by decomposers (bacteria, fungi) and detritivores (earthworms, etc.). This chain plays a crucial role in recycling nutrients within an ecosystem. Because the detritus food chain is based on the breakdown and recycling of already existing organic material, it can be said that it maximizes the use of the energy that is already within the ecosystem. So in that way, it is very efficient in the use of the energy that is present. It is very important for nutrient cycling. The detritus food chain contributes greatly to the overall energy flow of an ecosystem. Hence, statement 2 is correct. Producers, such as plants, capture solar energy through photosynthesis, making them the base of the food chain with the highest energy content. As energy moves up the food chain, it decreases due to the 10% rule Hence, statement 3 is correct. Incorrect Solution: C Lindeman’s trophic efficiency rule, also known as the 10% law, states that only about 10% of the energy from one trophic level is transferred to the next, with the remaining 90% lost as heat or used for metabolic processes Hence, statement 1 is correct. Detritus food chain begins with dead organic matter (detritus), which is consumed by decomposers (bacteria, fungi) and detritivores (earthworms, etc.). This chain plays a crucial role in recycling nutrients within an ecosystem. Because the detritus food chain is based on the breakdown and recycling of already existing organic material, it can be said that it maximizes the use of the energy that is already within the ecosystem. So in that way, it is very efficient in the use of the energy that is present. It is very important for nutrient cycling. The detritus food chain contributes greatly to the overall energy flow of an ecosystem. Hence, statement 2 is correct. Producers, such as plants, capture solar energy through photosynthesis, making them the base of the food chain with the highest energy content. As energy moves up the food chain, it decreases due to the 10% rule Hence, statement 3 is correct.

#### 4. Question

Consider the following statements about energy flow in ecosystems:

• According to Lindeman’s efficiency, only about 10% of energy is transferred between trophic levels

• The detritus food chain is very efficient in recycling nutrients and utilizing the energy stored in dead organic matter

• The maximum energy in any food chain is concentrated at the producer level

How many of the statements given above are correct?

• (a) Only one

• (b) Only two

• (c) All three

Solution: C

Lindeman’s trophic efficiency rule, also known as the 10% law, states that only about 10% of the energy from one trophic level is transferred to the next, with the remaining 90% lost as heat or used for metabolic processes

Hence, statement 1 is correct.

Detritus food chain begins with dead organic matter (detritus), which is consumed by decomposers (bacteria, fungi) and detritivores (earthworms, etc.).

This chain plays a crucial role in recycling nutrients within an ecosystem. Because the detritus food chain is based on the breakdown and recycling of already existing organic material, it can be said that it maximizes the use of the energy that is already within the ecosystem.

So in that way, it is very efficient in the use of the energy that is present. It is very important for nutrient cycling. The detritus food chain contributes greatly to the overall energy flow of an ecosystem.

Hence, statement 2 is correct.

Producers, such as plants, capture solar energy through photosynthesis, making them the base of the food chain with the highest energy content. As energy moves up the food chain, it decreases due to the 10% rule

Hence, statement 3 is correct.

Solution: C

Hence, statement 1 is correct.

Detritus food chain begins with dead organic matter (detritus), which is consumed by decomposers (bacteria, fungi) and detritivores (earthworms, etc.).

Hence, statement 2 is correct.

Hence, statement 3 is correct.

• Question 5 of 30 5. Question 1 points Consider the following statements: Statement 1: Keystone species have a disproportionately large effect on community structure relative to their abundance. Statement 2: The removal of a keystone species necessarily leads to trophic cascades in all ecosystems. In light of the above statements, which one of the following is correct? (a) Both Statement 1 and Statement 2 are correct, and Statement 2 is the correct explanation of Statement 1 (b) Both Statement 1 and Statement 2 are correct, but Statement 2 is NOT the correct explanation of Statement 1 (c) Statement 1 is correct but Statement 2 is incorrect (d) Statement 1 is incorrect but Statement 2 is correct Correct Solution: C In ecological communities, certain species exert an influence on their environment that is disproportionately large compared to their abundance. These are known as keystone species. Their presence and roles are critical in maintaining the structure and diversity of their ecosystems. The concept of a keystone species was introduced by ecologist Robert T. Paine in 1969. He observed that certain species, despite their low biomass, have a significant impact on the composition and function of their ecosystems. For example, the removal of the sea star Pisaster ochraceus led to a dramatic decrease in biodiversity in intertidal zones, highlighting its role as a keystone predator. Hence, statement 1 is correct. While the removal of a keystone species can lead to trophic cascades—indirect effects that ripple through multiple trophic levels—this outcome is not universal across all ecosystems. The specific impact of removing a keystone species depends on the ecological context, including the presence of other species that might fulfil similar roles and the overall complexity of the food web. Therefore, trophic cascades are a possible but not an inevitable consequence of removing a keystone species. Hence, statement 2 is incorrect. Incorrect Solution: C In ecological communities, certain species exert an influence on their environment that is disproportionately large compared to their abundance. These are known as keystone species. Their presence and roles are critical in maintaining the structure and diversity of their ecosystems. The concept of a keystone species was introduced by ecologist Robert T. Paine in 1969. He observed that certain species, despite their low biomass, have a significant impact on the composition and function of their ecosystems. For example, the removal of the sea star Pisaster ochraceus led to a dramatic decrease in biodiversity in intertidal zones, highlighting its role as a keystone predator. Hence, statement 1 is correct. While the removal of a keystone species can lead to trophic cascades—indirect effects that ripple through multiple trophic levels—this outcome is not universal across all ecosystems. The specific impact of removing a keystone species depends on the ecological context, including the presence of other species that might fulfil similar roles and the overall complexity of the food web. Therefore, trophic cascades are a possible but not an inevitable consequence of removing a keystone species. Hence, statement 2 is incorrect.

#### 5. Question

Consider the following statements:

Statement 1:

Keystone species have a disproportionately large effect on community structure relative to their abundance. Statement 2:

The removal of a keystone species necessarily leads to trophic cascades in all ecosystems.

In light of the above statements, which one of the following is correct?

• (a) Both Statement 1 and Statement 2 are correct, and Statement 2 is the correct explanation of Statement 1

• (b) Both Statement 1 and Statement 2 are correct, but Statement 2 is NOT the correct explanation of Statement 1

• (c) Statement 1 is correct but Statement 2 is incorrect

• (d) Statement 1 is incorrect but Statement 2 is correct

Solution: C

In ecological communities, certain species exert an influence on their environment that is disproportionately large compared to their abundance. These are known as keystone species. Their presence and roles are critical in maintaining the structure and diversity of their ecosystems.

The concept of a keystone species was introduced by ecologist Robert T. Paine in 1969. He observed that certain species, despite their low biomass, have a significant impact on the composition and function of their ecosystems. For example, the removal of the sea star Pisaster ochraceus led to a dramatic decrease in biodiversity in intertidal zones, highlighting its role as a keystone predator.

Hence, statement 1 is correct.

While the removal of a keystone species can lead to trophic cascades—indirect effects that ripple through multiple trophic levels—this outcome is not universal across all ecosystems. The specific impact of removing a keystone species depends on the ecological context, including the presence of other species that might fulfil similar roles and the overall complexity of the food web. Therefore, trophic cascades are a possible but not an inevitable consequence of removing a keystone species.

Hence, statement 2 is incorrect.

Solution: C

Hence, statement 1 is correct.

Hence, statement 2 is incorrect.

• Question 6 of 30 6. Question 1 points The “One Health” approach, recently in news, recognizes the interconnection between: Human health Animal health Ecosystem health Economic health Select the correct answer using the code given below: (a) 1, 2 and 3 only (b) 2 and 4 only (c) 1, 3 and 4 only (d) 1, 2, 3 and 4 Correct Solution: A The One Health approach is a collaborative, multisectoral, and transdisciplinary strategy that aims to achieve optimal health outcomes by recognizing the interconnection between people, animals, plants, and their shared environment. This approach emphasizes that the health of humans, animals (both domestic and wild), and ecosystems are closely linked and interdependent. According to the World Health Organization (WHO), One Health is defined as “an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals, and ecosystems.” While economic health is influenced by the health of humans, animals, and ecosystems, it is not a primary focus of the One Health approach. Therefore, the One Health approach specifically recognizes the interconnection between human health, animal health, and ecosystem health. Hence, option (a) is correct. Incorrect Solution: A The One Health approach is a collaborative, multisectoral, and transdisciplinary strategy that aims to achieve optimal health outcomes by recognizing the interconnection between people, animals, plants, and their shared environment. This approach emphasizes that the health of humans, animals (both domestic and wild), and ecosystems are closely linked and interdependent. According to the World Health Organization (WHO), One Health is defined as “an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals, and ecosystems.” While economic health is influenced by the health of humans, animals, and ecosystems, it is not a primary focus of the One Health approach. Therefore, the One Health approach specifically recognizes the interconnection between human health, animal health, and ecosystem health. Hence, option (a) is correct.

#### 6. Question

The “One Health” approach, recently in news, recognizes the interconnection between:

• Human health

• Animal health

• Ecosystem health

• Economic health

Select the correct answer using the code given below:

• (a) 1, 2 and 3 only

• (b) 2 and 4 only

• (c) 1, 3 and 4 only

• (d) 1, 2, 3 and 4

Solution: A

The One Health approach is a collaborative, multisectoral, and transdisciplinary strategy that aims to achieve optimal health outcomes by recognizing the interconnection between people, animals, plants, and their shared environment. This approach emphasizes that the health of humans, animals (both domestic and wild), and ecosystems are closely linked and interdependent.

According to the World Health Organization (WHO), One Health is defined as “an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals, and ecosystems.”

While economic health is influenced by the health of humans, animals, and ecosystems, it is not a primary focus of the One Health approach. Therefore, the One Health approach specifically recognizes the interconnection between human health, animal health, and ecosystem health.

Hence, option (a) is correct.

Solution: A

Hence, option (a) is correct.

• Question 7 of 30 7. Question 1 points Consider the following pairs regarding recent environmental initiatives: Initiative Associated Organization 1. Living Planet Report 2024 UNEP 2. Global Biodiversity Framework Fund Green Climate Fund 3. International Year of Rangelands and Pastoralists FAO How many of the pairs given above is/are correctly matched? (a) Only one (b) Only two (c) All three (d) None Correct Solution: A The Living Planet Report is published every two years by the World Wide Fund for Nature (WWF), not the United Nations Environment Programme (UNEP). It provides a comprehensive study of trends in global biodiversity and the health of the planet, focusing on the Living Planet Index (LPI), which measures the state of the world’s biological diversity based on population trends of vertebrate species Hence, pair 1 is incorrect. The Global Biodiversity Framework Fund (GBFF) was established to support the implementation of the Kunming-Montreal Global Biodiversity Framework. It operates under the Global Environment Facility (GEF) Hence pair 2 is incorrect. The United Nations declared 2026 as the International Year of Rangelands and Pastoralists, with the Food and Agriculture Organization (FAO) designated as the lead agency for its implementation. Hence, pair 3 is correct. Incorrect Solution: A The Living Planet Report is published every two years by the World Wide Fund for Nature (WWF), not the United Nations Environment Programme (UNEP). It provides a comprehensive study of trends in global biodiversity and the health of the planet, focusing on the Living Planet Index (LPI), which measures the state of the world’s biological diversity based on population trends of vertebrate species Hence, pair 1 is incorrect. The Global Biodiversity Framework Fund (GBFF) was established to support the implementation of the Kunming-Montreal Global Biodiversity Framework. It operates under the Global Environment Facility (GEF) Hence pair 2 is incorrect. The United Nations declared 2026 as the International Year of Rangelands and Pastoralists, with the Food and Agriculture Organization (FAO) designated as the lead agency for its implementation. Hence, pair 3 is correct.

#### 7. Question

Consider the following pairs regarding recent environmental initiatives:

Initiative | Associated Organization

1.Living Planet Report 2024 | UNEP
2.Global Biodiversity Framework Fund | Green Climate Fund
3.International Year of Rangelands and Pastoralists | FAO

How many of the pairs given above is/are correctly matched?

• (a) Only one

• (b) Only two

• (c) All three

Solution: A

The Living Planet Report is published every two years by the World Wide Fund for Nature (WWF), not the United Nations Environment Programme (UNEP). It provides a comprehensive study of trends in global biodiversity and the health of the planet, focusing on the Living Planet Index (LPI), which measures the state of the world’s biological diversity based on population trends of vertebrate species

Hence, pair 1 is incorrect.

The Global Biodiversity Framework Fund (GBFF) was established to support the implementation of the Kunming-Montreal Global Biodiversity Framework. It operates under the Global Environment Facility (GEF)

Hence pair 2 is incorrect.

The United Nations declared 2026 as the International Year of Rangelands and Pastoralists, with the Food and Agriculture Organization (FAO) designated as the lead agency for its implementation.

Hence, pair 3 is correct.

Solution: A

Hence, pair 1 is incorrect.

Hence pair 2 is incorrect.

The United Nations declared 2026 as the International Year of Rangelands and Pastoralists, with the Food and Agriculture Organization (FAO) designated as the lead agency for its implementation.

Hence, pair 3 is correct.

• Question 8 of 30 8. Question 1 points Which of the following biogeochemical cycles does NOT have a significant atmospheric component? (a) Carbon cycle (b) Nitrogen cycle (c) Phosphorus cycle (d) Sulphur cycle Correct Solution: C Biogeochemical cycles describe the pathways through which essential elements move through the biotic and abiotic components of ecosystems. These cycles are crucial for maintaining the balance of nutrients necessary for life. They can be categorized into two types: gaseous and sedimentary. Gaseous cycles involve the atmosphere as a significant reservoir, while sedimentary cycles primarily involve the Earth’s crust. Phosphorus Cycle: The phosphorus cycle is unique among major biogeochemical cycles because it does not have a significant atmospheric component.: Reservoirs: Phosphorus is primarily stored in the Earth’s crust as phosphate minerals, in soils, and in water bodies as sediments. Unlike carbon, nitrogen, and sulphur, phosphorus does not have a gaseous form that significantly participates in the atmosphere. Movement: Phosphorus moves through ecosystems via weathering of rocks, absorption by plants, consumption by animals, decomposition, and sedimentation in water bodies. There is no significant gaseous phase in this cycle. Human Impact: Human activities like mining and the use of phosphate fertilizers can disrupt the phosphorus cycle, leading to issues like eutrophication in aquatic ecosystems. Incorrect Solution: C Biogeochemical cycles describe the pathways through which essential elements move through the biotic and abiotic components of ecosystems. These cycles are crucial for maintaining the balance of nutrients necessary for life. They can be categorized into two types: gaseous and sedimentary. Gaseous cycles involve the atmosphere as a significant reservoir, while sedimentary cycles primarily involve the Earth’s crust. Phosphorus Cycle: The phosphorus cycle is unique among major biogeochemical cycles because it does not have a significant atmospheric component.: Reservoirs: Phosphorus is primarily stored in the Earth’s crust as phosphate minerals, in soils, and in water bodies as sediments. Unlike carbon, nitrogen, and sulphur, phosphorus does not have a gaseous form that significantly participates in the atmosphere. Movement: Phosphorus moves through ecosystems via weathering of rocks, absorption by plants, consumption by animals, decomposition, and sedimentation in water bodies. There is no significant gaseous phase in this cycle. Human Impact: Human activities like mining and the use of phosphate fertilizers can disrupt the phosphorus cycle, leading to issues like eutrophication in aquatic ecosystems.

#### 8. Question

Which of the following biogeochemical cycles does NOT have a significant atmospheric component?

• (a) Carbon cycle

• (b) Nitrogen cycle

• (c) Phosphorus cycle

• (d) Sulphur cycle

Solution: C

Biogeochemical cycles describe the pathways through which essential elements move through the biotic and abiotic components of ecosystems. These cycles are crucial for maintaining the balance of nutrients necessary for life. They can be categorized into two types: gaseous and sedimentary. Gaseous cycles involve the atmosphere as a significant reservoir, while sedimentary cycles primarily involve the Earth’s crust.

Phosphorus Cycle:

The phosphorus cycle is unique among major biogeochemical cycles because it does not have a significant atmospheric component.:

• Reservoirs: Phosphorus is primarily stored in the Earth’s crust as phosphate minerals, in soils, and in water bodies as sediments. Unlike carbon, nitrogen, and sulphur, phosphorus does not have a gaseous form that significantly participates in the atmosphere.

• Movement: Phosphorus moves through ecosystems via weathering of rocks, absorption by plants, consumption by animals, decomposition, and sedimentation in water bodies. There is no significant gaseous phase in this cycle.

• Human Impact: Human activities like mining and the use of phosphate fertilizers can disrupt the phosphorus cycle, leading to issues like eutrophication in aquatic ecosystems.

Solution: C

Phosphorus Cycle:

The phosphorus cycle is unique among major biogeochemical cycles because it does not have a significant atmospheric component.:

• Human Impact: Human activities like mining and the use of phosphate fertilizers can disrupt the phosphorus cycle, leading to issues like eutrophication in aquatic ecosystems.

• Question 9 of 30 9. Question 1 points The “Rhizosphere” in an ecosystem primarily facilitates: (a) Atmospheric nitrogen fixation (b) Enhanced nutrient cycling through root-microbe interactions (c) Carbon sequestration via mycorrhizal networks (d) Soil erosion prevention Correct Solution: B The rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome. This zone is critical for plant growth, nutrient uptake, and overall ecosystem functioning due to the complex interactions between plant roots, soil, and microorganisms. In the rhizosphere, plants release various organic compounds, such as sugars, amino acids, and organic acids, through root exudates. These exudates serve as nutrients for soil microorganisms, stimulating their activity. In return, these microbes contribute to nutrient cycling by decomposing organic matter, solubilizing minerals like phosphorus, and fixing atmospheric nitrogen, thereby enhancing nutrient availability for plant uptake. While atmospheric nitrogen fixation does occur in the rhizosphere, it is just one aspect of the broader nutrient cycling processes facilitated by root-microbe interactions. Carbon sequestration via mycorrhizal networks and soil erosion prevention are also influenced by rhizospheric activities but are not the primary functions of the rhizosphere. Hence, option (b) is correct. Incorrect Solution: B The rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome. This zone is critical for plant growth, nutrient uptake, and overall ecosystem functioning due to the complex interactions between plant roots, soil, and microorganisms. In the rhizosphere, plants release various organic compounds, such as sugars, amino acids, and organic acids, through root exudates. These exudates serve as nutrients for soil microorganisms, stimulating their activity. In return, these microbes contribute to nutrient cycling by decomposing organic matter, solubilizing minerals like phosphorus, and fixing atmospheric nitrogen, thereby enhancing nutrient availability for plant uptake. While atmospheric nitrogen fixation does occur in the rhizosphere, it is just one aspect of the broader nutrient cycling processes facilitated by root-microbe interactions. Carbon sequestration via mycorrhizal networks and soil erosion prevention are also influenced by rhizospheric activities but are not the primary functions of the rhizosphere. Hence, option (b) is correct.

#### 9. Question

The “Rhizosphere” in an ecosystem primarily facilitates:

• (a) Atmospheric nitrogen fixation

• (b) Enhanced nutrient cycling through root-microbe interactions

• (c) Carbon sequestration via mycorrhizal networks

• (d) Soil erosion prevention

Solution: B

The rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome. This zone is critical for plant growth, nutrient uptake, and overall ecosystem functioning due to the complex interactions between plant roots, soil, and microorganisms.

In the rhizosphere, plants release various organic compounds, such as sugars, amino acids, and organic acids, through root exudates. These exudates serve as nutrients for soil microorganisms, stimulating their activity. In return, these microbes contribute to nutrient cycling by decomposing organic matter, solubilizing minerals like phosphorus, and fixing atmospheric nitrogen, thereby enhancing nutrient availability for plant uptake.

While atmospheric nitrogen fixation does occur in the rhizosphere, it is just one aspect of the broader nutrient cycling processes facilitated by root-microbe interactions. Carbon sequestration via mycorrhizal networks and soil erosion prevention are also influenced by rhizospheric activities but are not the primary functions of the rhizosphere.

Hence, option (b) is correct.

Solution: B

Hence, option (b) is correct.

• Question 10 of 30 10. Question 1 points Which ecological pyramid is most likely inverted in a temperate forest ecosystem? (a) Pyramid of numbers (b) Pyramid of biomass (c) Pyramid of energy (d) None of the above Correct Solution: A Ecological pyramids are graphical representations that illustrate the structure of ecosystems by depicting the distribution of numbers, biomass, or energy among trophic levels. The three primary types are: Pyramid of Numbers: Shows the number of individual organisms at each trophic level. Pyramid of Biomass: Represents the total biomass (the mass of living organisms) at each trophic level. Pyramid of Energy: Illustrates the flow of energy through each trophic level, always upright due to the laws of thermodynamics. In a temperate forest ecosystem, the pyramid of numbers can be inverted. This inversion occurs because a single large tree (producer) can support a vast number of herbivorous insects (primary consumers). For example, during the summer, a few large trees may serve as the base of the pyramid, while the number of primary consumers, mostly insects, is significantly higher. On the other hand, the pyramid of biomass in a temperate forest is typically upright. The large mass of the trees at the producer level exceeds the combined biomass of the consumers at higher trophic levels. The pyramid of energy is always upright, reflecting the decrease in available energy at successive trophic levels due to energy loss as heat Hence, option (a) is correct. Incorrect Solution: A Ecological pyramids are graphical representations that illustrate the structure of ecosystems by depicting the distribution of numbers, biomass, or energy among trophic levels. The three primary types are: Pyramid of Numbers: Shows the number of individual organisms at each trophic level. Pyramid of Biomass: Represents the total biomass (the mass of living organisms) at each trophic level. Pyramid of Energy: Illustrates the flow of energy through each trophic level, always upright due to the laws of thermodynamics. In a temperate forest ecosystem, the pyramid of numbers can be inverted. This inversion occurs because a single large tree (producer) can support a vast number of herbivorous insects (primary consumers). For example, during the summer, a few large trees may serve as the base of the pyramid, while the number of primary consumers, mostly insects, is significantly higher. On the other hand, the pyramid of biomass in a temperate forest is typically upright. The large mass of the trees at the producer level exceeds the combined biomass of the consumers at higher trophic levels. The pyramid of energy is always upright, reflecting the decrease in available energy at successive trophic levels due to energy loss as heat Hence, option (a) is correct.

#### 10. Question

Which ecological pyramid is most likely inverted in a temperate forest ecosystem?

• (a) Pyramid of numbers

• (b) Pyramid of biomass

• (c) Pyramid of energy

• (d) None of the above

Solution: A

Ecological pyramids are graphical representations that illustrate the structure of ecosystems by depicting the distribution of numbers, biomass, or energy among trophic levels. The three primary types are:

• Pyramid of Numbers: Shows the number of individual organisms at each trophic level.

• Pyramid of Biomass: Represents the total biomass (the mass of living organisms) at each trophic level.

• Pyramid of Energy: Illustrates the flow of energy through each trophic level, always upright due to the laws of thermodynamics.

In a temperate forest ecosystem, the pyramid of numbers can be inverted. This inversion occurs because a single large tree (producer) can support a vast number of herbivorous insects (primary consumers). For example, during the summer, a few large trees may serve as the base of the pyramid, while the number of primary consumers, mostly insects, is significantly higher.

On the other hand, the pyramid of biomass in a temperate forest is typically upright. The large mass of the trees at the producer level exceeds the combined biomass of the consumers at higher trophic levels. The pyramid of energy is always upright, reflecting the decrease in available energy at successive trophic levels due to energy loss as heat

Hence, option (a) is correct.

Solution: A

• Pyramid of Numbers: Shows the number of individual organisms at each trophic level.

• Pyramid of Biomass: Represents the total biomass (the mass of living organisms) at each trophic level.

• Pyramid of Energy: Illustrates the flow of energy through each trophic level, always upright due to the laws of thermodynamics.

Hence, option (a) is correct.

• Question 11 of 30 11. Question 1 points Consider the following: Mold Milipede Mollusc How many of the above are commonly known as Detrivores? (a) Only one (b) Only two (c) All three (d) None Correct Solution: B Mold is a fungal species, not a detrivore. Some molds can cause allergic reactions and respiratory problems; under specific conditions they produce mycotoxins that are poisonous substances, harmful for humans. Mold is a decomposer and plays a vital role in breaking down dead organic matter and recycling of nutrients back into the environment. Hence option 1 is incorrect Milipedes and Molluscs are Detrivores. Detrivores are organisms that feed upon the detritus (very small particles of dead remains of plants and animals) as well as fecal matter Unlike decomposers, Detrivores have intracellular digestion Most common examples of Detrivores include earthworms, millipedes, Molluscs, flies and crabs. Hence options 2 and 3 are correct Incorrect Solution: B Mold is a fungal species, not a detrivore. Some molds can cause allergic reactions and respiratory problems; under specific conditions they produce mycotoxins that are poisonous substances, harmful for humans. Mold is a decomposer and plays a vital role in breaking down dead organic matter and recycling of nutrients back into the environment. Hence option 1 is incorrect Milipedes and Molluscs are Detrivores. Detrivores are organisms that feed upon the detritus (very small particles of dead remains of plants and animals) as well as fecal matter Unlike decomposers, Detrivores have intracellular digestion Most common examples of Detrivores include earthworms, millipedes, Molluscs, flies and crabs. Hence options 2 and 3 are correct

#### 11. Question

Consider the following:

How many of the above are commonly known as Detrivores?

• (a) Only one

• (b) Only two

• (c) All three

Solution: B

• Mold is a fungal species, not a detrivore.

• Some molds can cause allergic reactions and respiratory problems; under specific conditions they produce mycotoxins that are poisonous substances, harmful for humans.

• Mold is a decomposer and plays a vital role in breaking down dead organic matter and recycling of nutrients back into the environment.

Hence option 1 is incorrect

• Milipedes and Molluscs are Detrivores.

• Detrivores are organisms that feed upon the detritus (very small particles of dead remains of plants and animals) as well as fecal matter

• Unlike decomposers, Detrivores have intracellular digestion

• Most common examples of Detrivores include earthworms, millipedes, Molluscs, flies and crabs.

Hence options 2 and 3 are correct

Solution: B

• Mold is a fungal species, not a detrivore.

• Some molds can cause allergic reactions and respiratory problems; under specific conditions they produce mycotoxins that are poisonous substances, harmful for humans.

• Mold is a decomposer and plays a vital role in breaking down dead organic matter and recycling of nutrients back into the environment.

Hence option 1 is incorrect

• Milipedes and Molluscs are Detrivores.

• Detrivores are organisms that feed upon the detritus (very small particles of dead remains of plants and animals) as well as fecal matter

• Unlike decomposers, Detrivores have intracellular digestion

• Most common examples of Detrivores include earthworms, millipedes, Molluscs, flies and crabs.

Hence options 2 and 3 are correct

• Question 12 of 30 12. Question 1 points Which of the following best describes the term Ecological niche? (a) The unique functional role and position of a species in its ecosystem (b) A geographically distinct population within a species adapted to particular conditions. (c) A naturally occurring community of flora and fauna occupying a major habitat (d) A phenomenon when a community has become resilient to occasional disturbances and its productivity does not vary from year to year Correct Solution: A Ecological niche is defined as the match of a species to a particular environmental condition; it describes how an organism or a population respond to the distribution of resources and the competitors present in an environment and how that species alters these factors to sustain itself in that particular condition. Niche refers to the unique functional role and position of a species in its habitat or ecosystem. Niche plays an essential role in the conservation of organisms. A niche is unique for a species; while many species share the habitat, no two species in a habitat can have the same niche, this is because of the competition with one another until one is displaced. Hence option A is correct Incorrect Solution: A Ecological niche is defined as the match of a species to a particular environmental condition; it describes how an organism or a population respond to the distribution of resources and the competitors present in an environment and how that species alters these factors to sustain itself in that particular condition. Niche refers to the unique functional role and position of a species in its habitat or ecosystem. Niche plays an essential role in the conservation of organisms. A niche is unique for a species; while many species share the habitat, no two species in a habitat can have the same niche, this is because of the competition with one another until one is displaced. Hence option A is correct

#### 12. Question

Which of the following best describes the term Ecological niche?

• (a) The unique functional role and position of a species in its ecosystem

• (b) A geographically distinct population within a species adapted to particular conditions.

• (c) A naturally occurring community of flora and fauna occupying a major habitat

• (d) A phenomenon when a community has become resilient to occasional disturbances and its productivity does not vary from year to year

Solution: A

• Ecological niche is defined as the match of a species to a particular environmental condition; it describes how an organism or a population respond to the distribution of resources and the competitors present in an environment and how that species alters these factors to sustain itself in that particular condition.

• Niche refers to the unique functional role and position of a species in its habitat or ecosystem.

• Niche plays an essential role in the conservation of organisms.

• A niche is unique for a species; while many species share the habitat, no two species in a habitat can have the same niche, this is because of the competition with one another until one is displaced.

Hence option A is correct

Solution: A

• Niche refers to the unique functional role and position of a species in its habitat or ecosystem.

• Niche plays an essential role in the conservation of organisms.

Hence option A is correct

• Question 13 of 30 13. Question 1 points Consider the following statements: Both Hydrarch and Xerarch Successions lead to medium water conditions. Angiosperms are the Pioneer species in case of primary succession in water. Which of the statements given above is/are correct? (a) 1only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2 Correct Solution: A Hydrarch succession takes place in wetter areas and the successional series progresses from hydric to mesic conditions Xerarch succession takes place in dry areas and the series progresses from xeric to mesic conditions. Hence both Hydrarch and Xerarch successions lead to medium water conditions (mesic)- neither too dry (xeric) nor too wet ( hydric). Hence statement 1 is correct Pioneer species refer to those species of plants and organisms which are first to colonize previously biodiverse steady-state ecosystems. Pioneer species are often hardy photosynthetic plants with significant adaptive properties like long roots, root nodules containing nitrogen fixing bacteria, etc. Pioneer species include both plants and certain organisms; example- algae, mosses, various types of grasses, orchids, lichens, etc. In primary succession in water, the pioneers are the phytoplanktons; they are replaced with time by free floating Angiosperms, then by rooted hydrophytes, grasses and finally the trees. Hence statement 2 is incorrect Incorrect Solution: A Hydrarch succession takes place in wetter areas and the successional series progresses from hydric to mesic conditions Xerarch succession takes place in dry areas and the series progresses from xeric to mesic conditions. Hence both Hydrarch and Xerarch successions lead to medium water conditions (mesic)- neither too dry (xeric) nor too wet ( hydric). Hence statement 1 is correct Pioneer species refer to those species of plants and organisms which are first to colonize previously biodiverse steady-state ecosystems. Pioneer species are often hardy photosynthetic plants with significant adaptive properties like long roots, root nodules containing nitrogen fixing bacteria, etc. Pioneer species include both plants and certain organisms; example- algae, mosses, various types of grasses, orchids, lichens, etc. In primary succession in water, the pioneers are the phytoplanktons; they are replaced with time by free floating Angiosperms, then by rooted hydrophytes, grasses and finally the trees. Hence statement 2 is incorrect

#### 13. Question

Consider the following statements:

• Both Hydrarch and Xerarch Successions lead to medium water conditions.

• Angiosperms are the Pioneer species in case of primary succession in water.

Which of the statements given above is/are correct?

• (b) 2 only

• (c) Both 1 and 2

• (d) Neither 1 nor 2

Solution: A

• Hydrarch succession takes place in wetter areas and the successional series progresses from hydric to mesic conditions

• Xerarch succession takes place in dry areas and the series progresses from xeric to mesic conditions.

• Hence both Hydrarch and Xerarch successions lead to medium water conditions (mesic)- neither too dry (xeric) nor too wet ( hydric).

Hence statement 1 is correct

• Pioneer species refer to those species of plants and organisms which are first to colonize previously biodiverse steady-state ecosystems.

• Pioneer species are often hardy photosynthetic plants with significant adaptive properties like long roots, root nodules containing nitrogen fixing bacteria, etc.

• Pioneer species include both plants and certain organisms; example- algae, mosses, various types of grasses, orchids, lichens, etc.

• In primary succession in water, the pioneers are the phytoplanktons; they are replaced with time by free floating Angiosperms, then by rooted hydrophytes, grasses and finally the trees.

Hence statement 2 is incorrect

Solution: A

• Hydrarch succession takes place in wetter areas and the successional series progresses from hydric to mesic conditions

• Xerarch succession takes place in dry areas and the series progresses from xeric to mesic conditions.

• Hence both Hydrarch and Xerarch successions lead to medium water conditions (mesic)- neither too dry (xeric) nor too wet ( hydric).

Hence statement 1 is correct

• Pioneer species refer to those species of plants and organisms which are first to colonize previously biodiverse steady-state ecosystems.

• Pioneer species are often hardy photosynthetic plants with significant adaptive properties like long roots, root nodules containing nitrogen fixing bacteria, etc.

• Pioneer species include both plants and certain organisms; example- algae, mosses, various types of grasses, orchids, lichens, etc.

• In primary succession in water, the pioneers are the phytoplanktons; they are replaced with time by free floating Angiosperms, then by rooted hydrophytes, grasses and finally the trees.

Hence statement 2 is incorrect

• Question 14 of 30 14. Question 1 points Consider the following statements: Secondary succession begins in areas where natural biotic community have been destroyed. At an anytime during secondary succession, Anthropogenic factors can convert a particular seral stage of succession to an earlier stage. Which of the statements given above is/are correct? (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2 Correct Solution: C The entire sequence of communities that successively change in a given area are called Sere(s). The individual transitional communities are termed seral communities or seral stage. Succession is a process that begins where no living organism is present- these could be areas where no living organisms ever existed or in areas that somehow lost all the living organisms that existed there ; the former is called primary succession while the latter is called secondary succession. Secondary succession begins in areas where natural biotic communities have been destroyed such as abandoned farmlands, burned or cut forests, lands that have been flooded and so on. At any time during primary or secondary succession, natural or human induced disturbances like fire, deforestation can convert a particular seral stage of succession to an earlier stage. Hence statements 1 and 2 are correct Incorrect Solution: C The entire sequence of communities that successively change in a given area are called Sere(s). The individual transitional communities are termed seral communities or seral stage. Succession is a process that begins where no living organism is present- these could be areas where no living organisms ever existed or in areas that somehow lost all the living organisms that existed there ; the former is called primary succession while the latter is called secondary succession. Secondary succession begins in areas where natural biotic communities have been destroyed such as abandoned farmlands, burned or cut forests, lands that have been flooded and so on. At any time during primary or secondary succession, natural or human induced disturbances like fire, deforestation can convert a particular seral stage of succession to an earlier stage. Hence statements 1 and 2 are correct

#### 14. Question

Consider the following statements:

• Secondary succession begins in areas where natural biotic community have been destroyed.

• At an anytime during secondary succession, Anthropogenic factors can convert a particular seral stage of succession to an earlier stage.

Which of the statements given above is/are correct?

• (a) 1 only

• (b) 2 only

• (c) Both 1 and 2

• (d) Neither 1 nor 2

Solution: C

• The entire sequence of communities that successively change in a given area are called Sere(s). The individual transitional communities are termed seral communities or seral stage.

• Succession is a process that begins where no living organism is present- these could be areas where no living organisms ever existed or in areas that somehow lost all the living organisms that existed there ; the former is called primary succession while the latter is called secondary succession.

• Secondary succession begins in areas where natural biotic communities have been destroyed such as abandoned farmlands, burned or cut forests, lands that have been flooded and so on.

• At any time during primary or secondary succession, natural or human induced disturbances like fire, deforestation can convert a particular seral stage of succession to an earlier stage.

Hence statements 1 and 2 are correct

Solution: C

• The entire sequence of communities that successively change in a given area are called Sere(s). The individual transitional communities are termed seral communities or seral stage.

• Secondary succession begins in areas where natural biotic communities have been destroyed such as abandoned farmlands, burned or cut forests, lands that have been flooded and so on.

• At any time during primary or secondary succession, natural or human induced disturbances like fire, deforestation can convert a particular seral stage of succession to an earlier stage.

Hence statements 1 and 2 are correct

• Question 15 of 30 15. Question 1 points Which reference to environment, which of the following best describes the term ‘Dieback mechanism? (a) An ecological phenomenon in which a part of the population of a particular species dies to sustain the healthier population (b) Death of large number of plants within a particular area due to lack of pollination (c) Dying of plants from backwards, from the tip of any portion of the plant (d) Production of a toxin by a species that is harmful for its own body under particular environmental conditions Correct Solution: C Dieback refers to the progressive dying in plants usually backwards from the tip of any portion of the plant. It typically starts at the tips and moves in towards the base; this can be seen in branches, roots or shoots. While dieback can be a natural part of life cycle of plants, it often indicates environmental stress, pest infestation or disease. In this mechanism the roots may remain alive for years but the shoots die It is one of the adaptive mechanisms exhibited by plants to avoid adverse conditions like drought Almost any plant can be affected by dieback from large trees to small hearts commonly affected species include fruit trees, Sal, red sandars, silk cotton trees, ornamental shrubs, etc. Hence option C is correct Incorrect Solution: C Dieback refers to the progressive dying in plants usually backwards from the tip of any portion of the plant. It typically starts at the tips and moves in towards the base; this can be seen in branches, roots or shoots. While dieback can be a natural part of life cycle of plants, it often indicates environmental stress, pest infestation or disease. In this mechanism the roots may remain alive for years but the shoots die It is one of the adaptive mechanisms exhibited by plants to avoid adverse conditions like drought Almost any plant can be affected by dieback from large trees to small hearts commonly affected species include fruit trees, Sal, red sandars, silk cotton trees, ornamental shrubs, etc. Hence option C is correct

#### 15. Question

Which reference to environment, which of the following best describes the term ‘Dieback mechanism?

• (a) An ecological phenomenon in which a part of the population of a particular species dies to sustain the healthier population

• (b) Death of large number of plants within a particular area due to lack of pollination

• (c) Dying of plants from backwards, from the tip of any portion of the plant

• (d) Production of a toxin by a species that is harmful for its own body under particular environmental conditions

Solution: C

• Dieback refers to the progressive dying in plants usually backwards from the tip of any portion of the plant.

• It typically starts at the tips and moves in towards the base; this can be seen in branches, roots or shoots.

• While dieback can be a natural part of life cycle of plants, it often indicates environmental stress, pest infestation or disease.

• In this mechanism the roots may remain alive for years but the shoots die

• It is one of the adaptive mechanisms exhibited by plants to avoid adverse conditions like drought

• Almost any plant can be affected by dieback from large trees to small hearts commonly affected species include fruit trees, Sal, red sandars, silk cotton trees, ornamental shrubs, etc.

Hence option C is correct

Solution: C

• Dieback refers to the progressive dying in plants usually backwards from the tip of any portion of the plant.

• It typically starts at the tips and moves in towards the base; this can be seen in branches, roots or shoots.

• While dieback can be a natural part of life cycle of plants, it often indicates environmental stress, pest infestation or disease.

• In this mechanism the roots may remain alive for years but the shoots die

• It is one of the adaptive mechanisms exhibited by plants to avoid adverse conditions like drought

• Almost any plant can be affected by dieback from large trees to small hearts commonly affected species include fruit trees, Sal, red sandars, silk cotton trees, ornamental shrubs, etc.

Hence option C is correct

• Question 16 of 30 16. Question 1 points Consider the following microorganisms: Blue- green Algae Rhizobium Clostridium How many of the above are capable of fixing atmospheric nitrogen ? (a) Only one (b) Only two (c) All three (d) None Correct Solution: C Nitrogen fixation is the conversion of inorganic molecular nitrogen in the atmosphere to ammonia or nitrate it is required so that plants and algae can make use of ammonia or nitrate for photosynthesis. Most of the nitrogen fixation in terrestrial ecosystem is carried out by symbiotic bacteria; for example, *Rhizobium, that lives in root nodules of leguminous plants The bacteria obtain food from plants and plants get usable nitrogen in their root nodules from the bacteria; when the plants die, they add nitrogen to the soil through their organic matter. Nitrogen fixation is also carried out by free living soil bacteria like the aerobic Azotobacterand the anaerobic Clostridium sp. In case of aquatic ecosystem nitrogen fixation is carried out by Cyanobacteria also called Blue green algae. Hence option C is correct Incorrect Solution: C Nitrogen fixation is the conversion of inorganic molecular nitrogen in the atmosphere to ammonia or nitrate it is required so that plants and algae can make use of ammonia or nitrate for photosynthesis. Most of the nitrogen fixation in terrestrial ecosystem is carried out by symbiotic bacteria; for example, Rhizobium, that lives in root nodules of leguminous plants The bacteria obtain food from plants and plants get usable nitrogen in their root nodules from the bacteria; when the plants die, they add nitrogen to the soil through their organic matter. Nitrogen fixation is also carried out by free living soil bacteria like the aerobic Azotobacterand the anaerobic Clostridium sp. In case of aquatic ecosystem nitrogen fixation is carried out by Cyanobacteria also called Blue green algae. Hence option C is correct *

#### 16. Question

Consider the following microorganisms:

• Blue- green Algae

• Rhizobium

• Clostridium

How many of the above are capable of fixing atmospheric nitrogen ?

• (a) Only one

• (b) Only two

• (c) All three

Solution: C

• Nitrogen fixation is the conversion of inorganic molecular nitrogen in the atmosphere to ammonia or nitrate it is required so that plants and algae can make use of ammonia or nitrate for photosynthesis.

• Most of the nitrogen fixation in terrestrial ecosystem is carried out by symbiotic bacteria; for example, *Rhizobium*, that lives in root nodules of leguminous plants

• The bacteria obtain food from plants and plants get usable nitrogen in their root nodules from the bacteria; when the plants die, they add nitrogen to the soil through their organic matter.

• Nitrogen fixation is also carried out by free living soil bacteria like the aerobic *Azotobacterand the anaerobic Clostridium* sp.

• In case of aquatic ecosystem nitrogen fixation is carried out by Cyanobacteria also called Blue green algae.

Hence option C is correct

Solution: C

• Most of the nitrogen fixation in terrestrial ecosystem is carried out by symbiotic bacteria; for example, *Rhizobium*, that lives in root nodules of leguminous plants

• The bacteria obtain food from plants and plants get usable nitrogen in their root nodules from the bacteria; when the plants die, they add nitrogen to the soil through their organic matter.

• Nitrogen fixation is also carried out by free living soil bacteria like the aerobic *Azotobacterand the anaerobic Clostridium* sp.

• In case of aquatic ecosystem nitrogen fixation is carried out by Cyanobacteria also called Blue green algae.

Hence option C is correct

• Question 17 of 30 17. Question 1 points Consider the following statements: Statement – I: Pyramid of Energy is always inverted. Statement – II: Energy flow always decreases successively up the trophic level. Which of the following is correct in respect of the above statements? (a) Both Statement -I and Statement -II are correct and Statement -II explains Statement -I (b) Both Statement -I and Statement -II are correct but Statement -II does not explain Statement -I (c) Statement- I is correct but Statement -II is incorrect (d) Statement- I is incorrect but Statement -II is correct Correct Solution: D Ecological pyramids refer to graphical representation of trophic structures of an ecosystem based on different parameters; the following parameters are used for studying ecological pyramids: Number of individuals at each tropic level of an ecosystem Dry weight of biomass of organisms at each trophic level of an ecosystem Rate of energy flow through different trophic levels of an ecosystem The pyramid of energy denotes the rate of energy flow. It is defined as graphical representation of the rate of total energy flow at successive trophic levels. Pyramid of energy is always upright and can never be inverted. This is because when energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step. Each bar in the energy pyramid indicates the amount of energy present at each trophic level in a given time or annually per unit area Hence statement 1 is incorrect and statement 2 is correct Incorrect Solution: D Ecological pyramids refer to graphical representation of trophic structures of an ecosystem based on different parameters; the following parameters are used for studying ecological pyramids: Number of individuals at each tropic level of an ecosystem Dry weight of biomass of organisms at each trophic level of an ecosystem Rate of energy flow through different trophic levels of an ecosystem The pyramid of energy denotes the rate of energy flow. It is defined as graphical representation of the rate of total energy flow at successive trophic levels. Pyramid of energy is always upright and can never be inverted. This is because when energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step. Each bar in the energy pyramid indicates the amount of energy present at each trophic level in a given time or annually per unit area Hence statement 1 is incorrect and statement 2 is correct

#### 17. Question

Consider the following statements:

Statement – I:

Pyramid of Energy is always inverted.

Statement – II:

Energy flow always decreases successively up the trophic level.

Which of the following is correct in respect of the above statements?

• (a) Both Statement -I and Statement -II are correct and Statement -II explains Statement -I

• (b) Both Statement -I and Statement -II are correct but Statement -II does not explain Statement -I

• (c) Statement- I is correct but Statement -II is incorrect

• (d) Statement- I is incorrect but Statement -II is correct

Solution: D

Ecological pyramids refer to graphical representation of trophic structures of an ecosystem based on different parameters; the following parameters are used for studying ecological pyramids:

• Number of individuals at each tropic level of an ecosystem

• Dry weight of biomass of organisms at each trophic level of an ecosystem

• Rate of energy flow through different trophic levels of an ecosystem

The pyramid of energy denotes the rate of energy flow. It is defined as graphical representation of the rate of total energy flow at successive trophic levels.

• Pyramid of energy is always upright and can never be inverted.

• This is because when energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step.

• Each bar in the energy pyramid indicates the amount of energy present at each trophic level in a given time or annually per unit area

Hence statement 1 is incorrect and statement 2 is correct