Why is digestion a necessary process for animals?

The process by which food is broken down into simple chemical compounds that can be absorbed and used as nutrients or eliminated by the body. In most animals, nutrients are obtained from food by the action of digestive enzymes. ... In protists and some invertebrates, digestion occurs by phagocytosis. read more

Digestion is the process by which the body obtains nutrients from the environment, notes Wikipedia. Without these nutrients, a living body would gradually run out of the energy necessary to maintain health. Eventually, a body that can no longer digest food starves to death. read more