Explore topic-wise MCQs in Biology.

This section includes 15 Mcqs, each offering curated multiple-choice questions to sharpen your Biology knowledge and support exam preparation. Choose a topic below to get started.

1.

For releasing CO2 in the atmosphere, how are fossil fuels exploited?

A. Mined and burned
B. Fragmented and leached
C. Leached and burned
D. Mined and fragmented
Answer» B. Fragmented and leached
2.

Which one of the following plants use as a source for carbon dioxide?

A. Carbonate rocks
B. Calcium rocks
C. Fossils
D. Atmospheric CO2
Answer» E.
3.

What product does the plants from by photosynthesis using carbon dioxide?

A. Lipids
B. Carbohydrates
C. Proteins
D. Salts
Answer» C. Proteins
4.

In which form does the carbon dioxide precipitate after dissolving in water?

A. Calcium oxide
B. Carbon mono-oxide
C. Calcium carbonate
D. Calcium phosphate
Answer» D. Calcium phosphate
5.

Which human activities have significantly influenced the carbon cycle?

A. Afforestation
B. Deforestation only
C. Burning of fossil fuel only
D. Both deforestation and burning of fossil fuel
Answer» E.
6.

Which of the following organism contributes to the CO2 pool by the processing of waste materials and dead organic matter?

A. Carnivores
B. Herbivores
C. Decomposers
D. Producers
Answer» D. Producers
7.

By which process does the carbon return to the atmosphere as CO2?

A. Decayed organisms
B. Calcareous sediments
C. Photosynthesis
D. Respiration
Answer» E.
8.

What amount of carbon is fixed in the biosphere through photosynthesis annually?

A. 1013 kg
B. 20 × 1020 kg
C. 4 × 1013 kg
D. 80 × 1035 kg
Answer» D. 80 × 1035 kg
9.

From which stages does the carbon cycling occur?

A. Dead organisms → Living organisms → Oceans
B. Atmosphere → Living organisms → Dead organisms
C. Oceans → Atmosphere → Dead organisms
D. Atmosphere → Oceans → Living organisms → Dead organisms
Answer» E.
10.

Whose reservoir does fossil fuel represent?

A. Oxygen
B. Carbon
C. Helium
D. Argon
Answer» C. Helium
11.

What percent of total global carbon does the atmosphere contain?

A. 5 %
B. 50 %
C. 1%
D. 20 %
Answer» D. 20 %
12.

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

A. Gaseous reservoir
B. Sedimentary reservoir
C. Atmospheric reservoir
D. Oceanic reservoir
Answer» E.
13.

Out of the total quantity of global carbon, what percent of carbon is found dissolved in oceans?

A. 50 %
B. 71 %
C. 90 %
D. 25 %
Answer» C. 90 %
14.

Which is the most abundant constituent found in living organisms?

A. Water
B. Oxygen
C. Ammonia
D. Hydrogen bicarbonate
Answer» B. Oxygen
15.

What percent of dry weight does carbon constitute in the living organisms?

A. 55 percent
B. 49 percent
C. 20 percent
D. 90 percent
Answer» C. 20 percent