Which substance is required by plants for photosynthesis and is released into the environment by animals as a waste product?

• A. Glucose (\(\mathrm{C_6H_{12}O_6}\))
• B. Oxygen (\(\mathrm{O_2}\))
• C. Nitrogen (\(\mathrm{N_2}\))
• D. Carbon dioxide (\(\mathrm{CO_2}\))

Answer: (D)

Verified step by step guidance

1. Step 1: Begin by understanding the process of photosynthesis. Photosynthesis is the process by which plants convert light energy into chemical energy, using carbon dioxide (\(\mathrm{CO_2}\)) and water (\(\mathrm{H_2O}\)) to produce glucose (\(\mathrm{C_6H_{12}O_6}\)) and oxygen (\(\mathrm{O_2}\)).
2. Step 2: Recognize the role of carbon dioxide (\(\mathrm{CO_2}\)) in photosynthesis. It is one of the key reactants that plants absorb from the environment to synthesize glucose during the Calvin cycle.
3. Step 3: Understand the relationship between animals and plants. Animals release carbon dioxide (\(\mathrm{CO_2}\)) as a waste product during cellular respiration, which is then utilized by plants for photosynthesis.
4. Step 4: Eliminate the incorrect options. Glucose (\(\mathrm{C_6H_{12}O_6}\)) is a product of photosynthesis, not a required substance. Oxygen (\(\mathrm{O_2}\)) is also a product of photosynthesis, and nitrogen (\(\mathrm{N_2}\)) is not directly involved in the photosynthesis process.
5. Step 5: Conclude that carbon dioxide (\(\mathrm{CO_2}\)) is the correct answer, as it is required by plants for photosynthesis and is released into the environment by animals as a waste product.