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

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

Which is the natural reservoir of Phosphorous?

1. Ocean

2. Fossils

3. Rock

4. Soil

How do herbivores and other animals obtain Phosphorous?

1. From soil in the dissolved form

2. From plants

3. From drinking water

4. Synthesized in the body.

The waste products and the dead organisms are decomposed by ____________releasing phosphorus.

1. parasitic bacteria

2. phosphate-solubilising bacteria

3. phosphate-solubilising fungi

4. Acidic soil.