Which product of cellular respiration is used as a reactant in photosynthesis?

• A. Lactic acid
• B. ATP
• C. Glucose (\(\mathrm{C_6H_{12}O_6}\))
• D. Carbon dioxide (\(\mathrm{CO_2}\))

Answer: (D)

Verified step by step guidance

1. Understand the relationship between cellular respiration and photosynthesis: Cellular respiration breaks down glucose (\(\mathrm{C_6H_{12}O_6}\)) to produce energy, releasing carbon dioxide (\(\mathrm{CO_2}\)) as a byproduct. Photosynthesis uses carbon dioxide (\(\mathrm{CO_2}\)) to produce glucose (\(\mathrm{C_6H_{12}O_6}\)) and oxygen (\(\mathrm{O_2}\)).
2. Identify the products of cellular respiration: Cellular respiration produces carbon dioxide (\(\mathrm{CO_2}\)), water (\(\mathrm{H_2O}\)), and ATP (adenosine triphosphate).
3. Determine which product of cellular respiration is used in photosynthesis: Photosynthesis requires carbon dioxide (\(\mathrm{CO_2}\)) as a reactant to synthesize glucose (\(\mathrm{C_6H_{12}O_6}\)).
4. Eliminate incorrect options: Lactic acid is produced during anaerobic respiration, not cellular respiration. ATP is an energy molecule used in various cellular processes but is not directly involved in photosynthesis as a reactant.
5. Conclude that the correct answer is carbon dioxide (\(\mathrm{CO_2}\)), as it is the product of cellular respiration that serves as a reactant in photosynthesis.