Here's why:

* Photosynthesis is the process where plants, algae, and some bacteria use sunlight, water, and carbon dioxide to create glucose (a type of sugar) and oxygen. This glucose is the cell's primary energy source.

* The energy from sunlight is converted into chemical energy stored in the bonds of glucose molecules.

* This stored energy can be accessed through cellular respiration, which breaks down glucose to release energy for the cell's activities.

Let me know if you'd like to learn more about photosynthesis or cellular respiration!