Q. No.What is the annual net primary productivity of the whole biosphere
1. 160 billion tons
2. 170 billion tons
3. 177 billion tons
4. 190 billion tons
Which of the following contributes the maximum to the net primary productivity?
1. Ocean ecosystem
2. Land ecosystem
3. Pond ecosystem
4. Man-made ecosystem
Why do we call the earthworm as the farmer’s friend?
| 1. | It eats the pests. |
| 2. | It prevents the growth of weeds. |
| 3. | It makes the soil fertile by burrowing. |
| 4. | It helps in the breakdown of complex organic matter as well as in loosening of the soil. |
Which of the following is not a step in the process of decomposition?
1. Fragmentation
2. Leaching
3. Anabolism
4. Humification.
Which of the following statement is correct?
1. Dead plant and animals remains, including fecal matter, constitute detritus,
2. Detritus is the product of decomposition.
3. Breakdown of complex inorganic matter into organic substances like CO₂ and nutrients is called as decomposition.
4. Decomposition is a single step process.
What is the process by which Detritivores break down the detritus into smaller particles.?
1. Degradation
2. Decomposition
3. Fragmentation
4. Leaching
What does the process of leaching refers to-
| 1. | Accumulation of a dark coloured amorphous substance |
| 2. | Organic solvents reabsorbed by the plants |
| 3. | Inorganic solvents get precipitated out of the soil |
| 4. | Water soluble inorganic nutrients go down into the soil horizon and get precipitated as unavailable salts. |
In the process of decomposition ‘catabolism’ is performed by-
1. Earthworms
2. Bacteria
3. Bacteria and fungi
4. Fungi
Which of the following statement is incorrect?
| 1. | All the steps in decomposition operate simultaneously on the humus. |
| 2. | Humus is an accumulated dark coloured amorphous substance. |
| 3. | Humus is highly resistant to microbial action and undergoes decomposition at an extremely slow rate. |
| 4. | Being colloidal in nature humus serves as a reservoir of nutrients. |
Which of the following is the substrate in the process of mineralisation?
1. Detritus
2. Humus
3. Organic matter
4. None of the above
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