1. | 25 % of the annual net primary productivity of the whole biosphere |
2. | 33 % of the annual net primary productivity of the whole biosphere |
3. | 66 % of the annual net primary productivity of the whole biosphere |
4. | 70 % of the annual net primary productivity of the whole biosphere |
1. | A considerable amount of phosphorus enters the biosphere through the primary producers. |
2. | Fossil fuels represent the major reservoir of phosphorus. |
3. | Phosphorus cycling occurs through the atmosphere, ocean, and through living and dead organisms. |
4. | There is no respiratory release of phosphorus into the atmosphere. |
1. | begins with primary producers like grass |
2. | is the major conduit for energy flow in an aquatic ecosystem |
3. | is not made up of any decomposers |
4. | may be connected with the grazing food chain at some levels |
I. | The change in communities during ecological succession is orderly and sequential, parallel with the changes in the physical environment. |
II. | Secondary succession is faster than primary succession. |
III. | Usually, lichens are pioneer species during primary xerarch succession. |
1. | Only I |
2. | Only II |
3. | Both I and III |
4. | I, II and III |
Statement I: | Decomposition is a process in which the detritus is degraded into simpler substances by microbes. |
Statement II: | Decomposition is faster if the detritus is rich in lignin and chitin. |
1. | Statement I is incorrect but Statement II is correct. |
2. | Both Statement I and Statement II are correct. |
3. | Both Statement I and Statement II are incorrect. |
4. | Statement I is correct but Statement II is incorrect. |
Which one of the following will accelerate phosphorus cycle?
1. Rainfall and storms
2. Burning of fossil fuels
3. Volcanic activity
4. Weathering of rocks
1. Decomposition | 2. Catabolism |
3. Fragmentation | 4. Humification |
Identify the correct set of statements with regard to the properties of humus.
(a) | Highly resistant to microbial action |
(b) | Dark-colored amorphous substance |
(c) | End product of detritus food chain |
(d) | Reservoir of nutrients |
(e) | Undergoes decomposition very fast |
Choose the correct answer from the options given below:
1. (a), (b), and (d) only
2. (a),(b) and (e) only
3. (a) and (b) only
4. (b), (c), and (a)