1. **Stating the problem:** The question asks about the primary role of sunlight in the light-dependent reactions of photosynthesis. 2. **Understanding the light-dependent reactions:** These reactions occur in the thylakoid membranes of chloroplasts and require light energy. 3. **Role of sunlight:** Sunlight provides energy that excites electrons in chlorophyll molecules. 4. **What happens next:** Excited electrons move through the electron transport chain, leading to the production of ATP and NADPH. 5. **Clarifying misconceptions:** Sunlight does not directly provide energy for glucose synthesis; that happens in the Calvin cycle (light-independent reactions) using ATP and NADPH. 6. **Conclusion:** Therefore, the primary role of sunlight in the light-dependent reactions is to excite electrons in chlorophyll to drive ATP and NADPH production.