photosynthesis
The way plants use sunlight to make their own food.
Photosynthesis is the process plants use to turn sunlight into food. Plants capture energy from the sun and combine it with water from the soil and carbon dioxide from the air to create sugar, which they use to grow and stay alive. As a bonus, they release oxygen into the air, which is pretty convenient for animals like us who need oxygen to breathe.
Inside plant leaves are tiny structures called chloroplasts that contain a green pigment called chlorophyll. This chlorophyll is what makes plants green, and it's the key ingredient that captures sunlight and starts the whole process.
Think of photosynthesis as a kind of solar-powered factory. The leaves are the factory, sunlight is the power source, and the plant produces its own food while helping keep the air full of oxygen. Without photosynthesis, there would be no plants, no oxygen in the atmosphere, and no food chain supporting animal life. Every time you eat a salad, a piece of fruit, or even a hamburger (since the cow ate plants), you're benefiting from photosynthesis. It's one of the most important chemical processes on Earth.