We know that the animals, fungi, bacteria, non-green plants and human being do not .have the ability to make their own food. They depend upon autotrophs for their food directly or indirectly. The green plant (leafy vegetables/grass) trap solar energy and make their own food in the form of glucose. So, we can say that leafy vegetables and grass can provide sufficient energy to help us survive. But, we cannot survive only on raw, ready vegetables since they have cellulose and humans are not able to digest cellulose.
