What are the inputs for photosynthesis?

• A. Carbon dioxide, water, and sunlight
• B. Glucose and oxygen
• C. Soil minerals and water
• D. Nitrogen and phosphorus

Answer: (A)

The key idea is that photosynthesis uses three inputs: carbon dioxide from the air, water taken up by the plant, and light energy from the sun. Light energy powers the reactions in chloroplasts, splitting water to release oxygen and providing electrons, while carbon dioxide is fixed into sugars through the Calvin cycle. The plant then yields glucose and oxygen as products. Soil minerals and nitrogen or phosphorus are important for overall plant health but are not direct inputs to the photosynthesis chemical reaction, and glucose and oxygen are the products, not the inputs.