The process of using energy to make food is called photosynthesis.

Here's a breakdown:

* Photosynthesis is the process used by plants, algae, and some bacteria to convert light energy from the sun into chemical energy in the form of glucose (a type of sugar). This glucose is then used as food by the organism.

* The energy source: The sun provides the energy needed for photosynthesis.

* The ingredients: Plants use carbon dioxide from the air, water from the ground, and sunlight to produce glucose and oxygen.

* The by-product: Oxygen is a byproduct of photosynthesis and is released into the atmosphere.

So, photosynthesis is the essential process that fuels life on Earth by converting sunlight into usable energy in the form of food.