The "Fruits" we are used to, are that fleshy and sweety layer which we all love to eat, but do you know what are fruits on a scientific meaning? In science, fruits are a layer generated from the ovary, which protects the seed to this to be ready for spawn a tree, for example. Also, they attract animals, and make them eat the seeds, to spread the sprouts.
Fruits
NEW PLANT
New plants repeat this amazing and nature created process based on photosynthesis, where they'll have food to grow up and give us O2 and fruits!