Question

the diagram shows two gases p and q in a gas cycle. which of the following are gases p and q?
p: nitrogen; q: carbon dioxide
p: carbon dioxide; q: oxygen
p: nitrogen; q: oxygen
p: oxygen; q: carbon dioxide

Explanation:

Step1: Analyze photosynthesis

Photosynthesis uses carbon dioxide (\(CO_2\)) and water (\(H_2O\)) to produce glucose (\(C_6H_{12}O_6\)) and oxygen (\(O_2\)). So gas \(P\) is oxygen (\(O_2\)).

Step2: Analyze combustion and respiration

Combustion and respiration processes consume oxygen (\(O_2\)) and produce carbon dioxide (\(CO_2\)). So gas \(Q\) is carbon dioxide (\(CO_2\)).

Answer:

P: Oxygen; Q: Carbon dioxide