* Photosynthesis: The process that allows plants to make their own food (glucose) is called photosynthesis. Photosynthesis relies heavily on light energy from the sun. This energy is absorbed by chlorophyll, the green pigment in plants, and used to convert carbon dioxide and water into glucose and oxygen.

* Other Energy Sources: Plants also use other energy sources, but to a lesser extent than light energy:

* Chemical energy: Plants obtain energy from the chemical bonds in glucose they produce during photosynthesis.

* Thermal energy: Plants absorb thermal energy from their environment to regulate their temperature.

In short: Light energy is the primary fuel that powers the majority of plant processes, making it the most crucial energy source for plant survival and growth.