In an introduction to photosynthesis, what type of energy do plants use to convert CO2 and H2O into sugars (e.g., glucose)?

• A. Chemical energy stored in ATP produced by cellular respiration
• B. Thermal energy (heat) from the environment
• C. Light energy from sunlight
• D. Mechanical energy generated by wind movement across leaves

Answer: (C)

Verified step by step guidance

1. Understand that photosynthesis is the process by which plants convert carbon dioxide (CO2) and water (H2O) into sugars like glucose.
2. Recognize that this conversion requires energy input to drive the chemical reactions, specifically the light-dependent reactions.
3. Identify the source of this energy as light energy, which plants capture from sunlight using pigments like chlorophyll.
4. Know that light energy is transformed into chemical energy stored in molecules such as ATP and NADPH during the light-dependent reactions.
5. Conclude that the initial energy driving photosynthesis is light energy from sunlight, not chemical energy from cellular respiration, thermal energy, or mechanical energy.