Question

where do photosynthetic organisms get the energy needed to make sugars during the light-independent/dark reactions?
○ they use the adp and carbon dioxide produced during the light-dependent reactions.
○ they convert the 6-carbon sugars into 5-carbon sugars.
○ they use the atp and nadph that are produced during the light-dependent reactions.
○ they obtain the energy directly from the sun.

Explanation:

1. Analyze the first option: Light - dependent reactions produce ATP (not ADP as a main energy - carrying molecule for dark reactions) and NADPH, and carbon dioxide is a raw material, not an energy source. So this option is wrong.
2. Analyze the second option: Converting 6 - carbon sugars to 5 - carbon sugars is part of the Calvin cycle (dark reactions) but not related to obtaining energy for sugar production. So this option is wrong.
3. Analyze the third option: In photosynthesis, light - dependent reactions produce ATP and NADPH. These molecules carry the energy and reducing power needed for the light - independent (dark) reactions (Calvin cycle) to synthesize sugars from carbon dioxide. This option is correct.
4. Analyze the fourth option: Light - independent reactions do not directly use energy from the Sun. The Sun's energy is captured in light - dependent reactions and then transferred to ATP and NADPH. So this option is wrong.

Answer:

C. They use the ATP and NADPH that are produced during the light - dependent reactions. (Here we assume the options are labeled A, B, C, D in order, with the third option being C)