The energy used in the process of photosynthesis is light energy from the sun.

Here's a breakdown:

* Photosynthesis is the process where plants, algae, and some bacteria use sunlight to convert carbon dioxide and water into glucose (sugar) and oxygen.

* Light energy is absorbed by chlorophyll, a pigment found in plants, which gives them their green color.

* This absorbed light energy is then used to power the chemical reactions that transform carbon dioxide and water into glucose and oxygen.

So, the sunlight provides the energy for photosynthesis to occur.