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

How much of the total quantity of global carbon is dissolved in the oceans?

1. 50%

2. 62%

3. 71%

4. 84%

Which of the following reservoir regulates the amount of carbon dioxide in the atmosphere?

1. Ocean

2. Earth’s crust

3. Land

4. Fossil

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