Plants make their own food through a process known as photosynthesis, which involves creating energy from sunlight, water, carbon dioxide and other nutrients. The substance in plants that makes the energy is known as chlorophyll, which is located in the leaves and is what gives plants their green color.
Chlorophyll is responsible for turning the necessary ingredients into carbohydrates that the plant can then consume for energy. This process takes place within a structure known as a chloroplast. The necessary carbon dioxide is taken in through small holes on the leaf known as stomata, which also release oxygen during the process.
For photosynthesis to happen, six molecules of carbon dioxide and six molecules of water join together in a chemical reaction when stimulated by light energy. The reaction of the two compounds results in the formation of C6H12O6, a complex sugar, and six molecules of 02 or oxygen gas. This resulting oxygen gas is the primary source of oxygen that humans and other animals breathe, meaning animal life could not exist without plants producing oxygen through photosynthesis.
The sugar that is formed through photosynthesis is stored in a chemical known as adenosine triphosphate or ATP, which has a very similar chemical makeup to the DNA found in animals.