1. the main function of the digestive is to

a. break down large molecules into small molecules and absorb nutrients
b. excrete oxygen and carbon dioxide
c. synthesize minerals and vitamins needed for a healthy body
d. remove waste products from the blood

2. the basic unit of structure and function in the nervous system are

a. neurons
b. axons
c. dendrites
d. neurotransmitters

3. the central nervous system consists of

a. sense organs
b. reflexes
c. brain and spinal cord
d. sensory and motor neurons