The digestive system first breaks down the food into its components, which are then used by the other systems of the body to keep the organism as a whole, including the brain, functioning properly.
(The digestive system; breaks down; the food; T:first) (its components; are used; by the other systems of the body; to keep the organism as a whole; T:then)
The digestive system its components
breaks down are used
the food T:first
by the other systems of the body to keep the organism as a whole T:then