Which component of Earth's atmosphere is decreased as a direct result of photosynthesis?

• A. Oxygen (O\(_2\))
• B. Water vapor (H\(_2\)O)
• C. Carbon dioxide (CO\(_2\))
• D. Nitrogen (N\(_2\))

Answer: (C)

Verified step by step guidance

1. Understand the process of photosynthesis: Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy, using carbon dioxide (CO\(_2\)) and water (H\(_2\)O) to produce glucose (C\(_6\)H\(_{12}\)O\(_6\)) and oxygen (O\(_2\)).
2. Identify the reactants and products of photosynthesis: The reactants are carbon dioxide (CO\(_2\)) and water (H\(_2\)O), while the products are glucose (C\(_6\)H\(_{12}\)O\(_6\)) and oxygen (O\(_2\)).
3. Focus on the role of carbon dioxide (CO\(_2\)): During photosynthesis, carbon dioxide is absorbed from the atmosphere by plants and used in the Calvin cycle to form glucose. This directly decreases the concentration of CO\(_2\) in the atmosphere.
4. Eliminate other options: Oxygen (O\(_2\)) is released as a byproduct of photosynthesis, so its concentration increases. Water vapor (H\(_2\)O) is used in the process but is not significantly decreased in the atmosphere. Nitrogen (N\(_2\)) is not involved in photosynthesis and remains unaffected.
5. Conclude that the correct answer is carbon dioxide (CO\(_2\)), as it is the atmospheric component directly decreased during photosynthesis.