Why does nutrients are never lost from the ecosystem?

1. Because they get transferred among various trophic levels.

2. Because they get recycled

3. Because they never get exhausted

4. Because they are required in very low quantity.

What do we call to the the movement of nutrient elements through the various components of
an ecosystem ?

1. Recycling

2. nutrient cycling

3. Biogeochemical cycle

4. Both 2 and 3.

Where do we find reservoir for gaseous type nutrient cycling?

1. Land

2. Sea

3. Earth’s crust

4. Atmosphere

Where do we find reservoir for sedimentary type nutrient cycling?

1. Land

2. Sea

3. Earth’s crust

4. Atmosphere

The rate of release of nutrients into the atmosphere is regulated by –

1. pH and moisture

2. Temperature

3. Soil

4. All of the above.

What per cent of the dry weight of organisms constitutes carbon?

1. 17%

2. 28%

3. 49%

4. 67%

Which is the second abundant matter in the body of an organism?

1. Phosphorous

2. Hydrogen

3. Carbon

4. Calcium

Approximately how much of carbon is fixed in the biosphere through photosynthesis annually.

1. 4 × ${10}^{13}$ kg

2. 5.4 x ${10}^{15}$ kg

3. 6.4 x ${10}^{11}$ kg

4. 13 x ${10}^4$ kg

Which of the following contribute to the atmospheric CO₂?
1. Producers
2. Herbivores
3. Saprotrophs
4. All of the above

How could human activities affect the carbon cycle?
1. By rapid forestation
2. By massive burning of fossil fuel for energy and transport
3. By forest fire
4. More than one of the options given above are correct