Assertion (A): | The earthworm has been referred to as a farmer’s ‘friend’ |
Reason (R): | They help in the breakdown of complex organic matter as well as in loosening of the soil. |
1. | Both (A) and (R) are True and (R) correctly explains (A). |
2. | (A) is True but (R) is False |
3. | (A) is False but (R) is True |
4. | Both (A) and (R) are True but (R) does not correctly explain (A). |
I: | is dead plant remains such as leaves, bark, flowers and dead remains of animals, including fecal matter. |
II: | is the raw material for decomposition. |
I: | Fragmentation | Detritivores break down detritus into smaller particles. |
II: | Leaching | Water-soluble inorganic nutrients go down into the soil horizon and get precipitated as unavailable salts. |
III: | Catabolism | Bacterial and fungal enzymes degrade detritus into simpler inorganic substances. |
Assertion (A): | Detritivores play an important role as recyclers in the ecosystem's energy flow and biogeochemical cycles. |
Reason (R): | Detritivores, alongside decomposers, reintroduce vital elements such as carbon, nitrogen, back into the soil, allowing plants to take in these elements and use them for growth. |
1. | Both (A) and (R) are True and (R) correctly explains (A). |
2. | Both (A) and (R) are True but (R) does not correctly explain (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
If decomposers go extinct on Earth:
1. | Detritivores will replace them |
2. | Primary production will increase |
3. | Nutrients will accumulate in dead plants and animals |
4. | There will be no effect on carnivores |
1. | is formed by humification of detritus as the first step of decomposition in an ecosystem. |
2. | is highly prone to rapid microbial action. |
3. | serves as a reservoir of nutrients. |
4. | is never degraded further in an ecosystem. |
During the decomposition of complex organic matter:
I: | Fragmentation of detritus creates smaller particles. |
II: | Due to leaching water-soluble inorganic nutrients get precipitated. |
III: | Catabolism by fungal and bacterial enzymes degrades detritus to simple organic monomers. |
IV: | Humus is highly resistant to microbial action |
V: | Mineralization is a rapid process of release of inorganic nutrients from the humus |
1. All except III are correct
2. All except III and IV are correct
3. All except III and V are correct
4. Only III is correct
Consider the given two statements:
I: | Humus has the ability to store nutrients. |
II: | Humus is a colloidal substance and increases the cation-exchange capacity of the soil. |
1. Both I and II are correct and II explains I.
2. Both I and II are correct but II does not explain I.
3. I is correct but II is incorrect.
4. I is incorrect but II is correct.
Statement I: | Humus is highly resistant to microbial action and undergoes decomposition at an extremely slow rate. |
Statement II: | Being colloidal in nature, humus serves as a reservoir of nutrients |
1. | Statement I is correct; Statement II is incorrect |
2. | Statement I is correct; Statement II is correct |
3. | Statement I is incorrect; Statement II is correct |
4. | Statement I is incorrect; Statement II is incorrect |
The process of mineralization by micro-organisms helps in the release of:
1. | Inorganic nutrients from humus |
2. | Both organic and inorganic nutrients from detritus |
3. | Organic nutrients from humus |
4. | Inorganic nutrients from detritus and formation of humus |