How plants use light to build themselves
Photosynthesis works like this: In the leaves and green stems of green plants there are specialized cells called chloroplasts. Within each chloroplast there are millions of molecules of a green pigment called chlorophyll that absorb the sun's energy.
When rays of sunlight hit the green leaves of a plant, each chloroplast traps the light energy and begins the conversion of light to chemical energy. The plant uses those chemicals to create glucose - with oxygen released as a byproduct during the process.
Just like humans, plants use the carbohydrates for energy to grow. Plants use this energy to make seeds, flowers, more leaves, stems, and fruits.
Without photosynthesis we would have nothing to eat or breathe - since both people and animals depend on plants for glucose and oxygen. To say the least: Photosynthesis is good.