In which type of reaction is CO2 typically required as a reactant?

• A. Combustion
• B. Photosynthesis
• C. Fermentation
• D. Respiration

Answer: (B)

Verified step by step guidance

1. Identify the types of reactions listed: Combustion, Photosynthesis, Fermentation, and Respiration.
2. Understand the role of CO2 in each reaction: CO2 is a product in combustion and respiration, not a reactant.
3. Recognize that photosynthesis is a process where plants use CO2, water, and sunlight to produce glucose and oxygen.
4. Note that in photosynthesis, CO2 is a crucial reactant as it is fixed into organic molecules.
5. Conclude that photosynthesis is the reaction type where CO2 is typically required as a reactant.