The stage of photosynthesis in which plants use the energy from ATP and NADPH to build high-energy sugars is called the Calvin cycle, also known as the light-independent reactions or the dark reactions.

Here's a breakdown:

* Light-dependent reactions: These reactions occur in the thylakoid membranes of chloroplasts and capture light energy to produce ATP and NADPH.

* Calvin cycle: These reactions occur in the stroma of chloroplasts and utilize the ATP and NADPH generated in the light-dependent reactions to convert carbon dioxide into glucose.

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