4. How is skeletal, skin and muscle interrelated?

A. They protect the internal organs of the body.

B. They supply oxygen and nutrients to the body.

C. They digest the food and convert it into energy.

D. They deliver messages to all systems of the body

5. How do digestive, respiratory and circulatory systems work together?

A. by digesting the food we eat

B. by breathing in oxygen needed by the body

C. by taking in oxygen and nutrients to the nervous system

D. by taking in oxygen and food nutrients to the different parts of the body​