Animals need plants for food, and plants also make oxygen which the animals need to live and breathe. Plants need animals for reproduction. For example: If an animal were to eat strawberries, the strawberry would digest, but the seeds would not - because it has a shell over it that protects it from the digestive enzymes and acids - so when the animal has later finished digesting and has to get rid of the waste, wherever it goes, the strawberry seeds would be deposited and a new plant would grow from them. Animals also breathe out carbon dioxide, which the plants use and turn into oxygen. So, in the cycle, the animal helps to create more plants for it to feed from and more plants to produce oxygen for them to live. The plants, in turn, are helped because of the animal's need of their resources.
Make sense?
Make sense?