How food is used in the animal's body

Food is digested.

When the animal eats, the food goes into the digestive tract. In the tract the food is changed and digested.

The digested part of the food enters the blood to feed the body. The rest is rejected as excrement.

When the greater part of the food enters the blood, the food is said to be rich.

When the greater part of the food is rejected, the food is said to be poor.

There are rich foods and poor foods.

Examples:

· Millet is rich food for certain animals. They can make good use of it. The greater part of it enters the blood. One kilogramme of crushed millet can give an animal's body as much strength as six kilogrammes of grass.

· Hard, stringy grasses in the dry season are a poor food for animals. The greater part of the dry grass does not enter the blood; it is rejected.