Question

Animals inhale gas A and exhale gas B. Gas A supports combustion. Gas B is used by plants to prepare their food. Identify gas A and gas B.

• A. A: nitrogen, B: oxygen
• B. A: oxygen, B: carbon dioxide
• C. A: carbon dioxide, B: oxygen
• D. A: oxygen, B: nitrogen

Answer 1

The correct option is B A: oxygen, B: carbon dioxide

During respiration, animals inhale oxygen and exhale carbon dioxide. Oxygen supports combustion. Hence gas A is oxygen.

Plants make their food by the process of photosynthesis. During this process, plants use carbon dioxide along with water to prepare their own food. Hence, gas B is carbon dioxide.