Answer:
Light energy
Step-by-step explanation:
Photosynthesis is a process that certain organisms called autotrophs, undergo to make their own food. Autotrophs are also called producers. Some examples of autotrophs/producers are plants and algae.
The photosynthesis equation is
carbon dioxide+water+light energy —> glucose+ oxygen
Carbon dioxide, water and light energy from the sun are turned into glucose (the food for the organism) and oxygen (waste product).
The sun provides the plant with light energy for photosynthesis. Therefore, the answer is light energy.