In an introduction to photosynthesis, which statement best describes how chemosynthesis differs from photosynthesis?

• A. Chemosynthesis produces oxygen as a byproduct, whereas photosynthesis does not produce oxygen.
• B. Chemosynthesis requires chlorophyll and sunlight, whereas photosynthesis does not require pigments.
• C. Chemosynthesis occurs only in plants, whereas photosynthesis occurs only in bacteria and archaea.
• D. Chemosynthesis uses energy from oxidizing inorganic chemicals to fix $C_0$2 into organic molecules, whereas photosynthesis uses light energy to fix $C_0$2.

Answer: (D)

Verified step by step guidance

1. Understand the basic definitions: Photosynthesis is the process by which organisms use light energy to convert carbon dioxide (CO\_2) and water into organic molecules and oxygen. Chemosynthesis, on the other hand, is a process where organisms produce organic molecules using energy derived from the oxidation of inorganic chemicals, not light.
2. Identify the energy source for each process: Photosynthesis relies on sunlight as the energy source, while chemosynthesis uses chemical energy from inorganic compounds such as hydrogen sulfide or ammonia.
3. Recognize the role of pigments: Photosynthesis requires pigments like chlorophyll to capture light energy. Chemosynthesis does not require pigments because it does not depend on light.
4. Note the byproducts: Photosynthesis typically produces oxygen as a byproduct due to the splitting of water molecules. Chemosynthesis does not produce oxygen as a byproduct because it uses different chemical reactions.
5. Summarize the key difference: Chemosynthesis fixes carbon dioxide into organic molecules using chemical energy from inorganic compounds, whereas photosynthesis fixes carbon dioxide using light energy.