Questions: What is the primary function of the Calvin cycle? use ATP to release carbon dioxide use NADPH to release carbon dioxide split water and release oxygen transport RuBP out of the chloroplast synthesize simple sugars from carbon dioxide

The answer is the last one: synthesize simple sugars from carbon dioxide.

Explanation for each option:

1. Use ATP to release carbon dioxide: This is incorrect. The Calvin cycle uses ATP, but its purpose is not to release carbon dioxide. Instead, it incorporates carbon dioxide into organic molecules.
2. Use NADPH to release carbon dioxide: This is incorrect. NADPH is used in the Calvin cycle to reduce carbon compounds, not to release carbon dioxide.
3. Split water and release oxygen: This is incorrect. The splitting of water and release of oxygen occurs during the light-dependent reactions of photosynthesis, not in the Calvin cycle.
4. Transport RuBP out of the chloroplast: This is incorrect. RuBP (ribulose bisphosphate) is a molecule that is regenerated within the Calvin cycle and is not transported out of the chloroplast.
5. Synthesize simple sugars from carbon dioxide: This is correct. The primary function of the Calvin cycle is to fix carbon dioxide and convert it into simple sugars like glucose, using the energy from ATP and the reducing power of NADPH.

Summary: The primary function of the Calvin cycle is to synthesize simple sugars from carbon dioxide.