Food is moved along the digestive system by muscles in the : I) oesophagus
II) stomach
III) small intestine

A : I only
B : I and II only
C : I and III only
D : All of the above

D. All of the above

Explanation:

The digestive system as a whole is made of muscles for moving of food further. The contraction and relaxation of the muscles enable the food to pass forward.

the answer is "a.) well–developed vascular system."

explanation:

the correct answer is d