Why Is Carbon Dioxide a Key Molecule in the Light-Independent

Multiple Choice

Why is carbon dioxide a key molecule in the light-independent (dark) reactions of photosynthesis?

A) CO₂ provides electrons to replace those lost by chlorophyll during the light-dependent reactions.
B) CO₂ provides the carbon for the synthesis of sugars during carbon fixation.
C) CO₂ is the major product of the light-independent reaction.
D) CO₂ provides the energy for substrate-level phosphorylation.