The reactants for the light-independent reaction (also known as the Calvin cycle) come from the light-dependent reactions. Here's a breakdown:

* CO₂: This is taken directly from the atmosphere.

* ATP: This is produced during the light-dependent reactions using energy from sunlight.

* NADPH: This is also produced during the light-dependent reactions, carrying high-energy electrons.

The light-dependent reactions provide the energy (ATP) and reducing power (NADPH) needed for the Calvin cycle to fix carbon dioxide and produce glucose. Think of it like this: the light-dependent reactions are the "power plant" of photosynthesis, generating the resources that the Calvin cycle needs to function.