Question

which of the following actions involves voluntary muscle movement?
○ movement of food through the digestive tract
○ movement of blood through the blood vessels
○ beating of the heart
○ making of faces

Explanation:

1. Movement of food through the digestive tract: This is done by smooth muscles (involuntary), so it's not voluntary.
2. Movement of blood through blood vessels: Involves smooth muscles (in blood vessel walls) and heart (cardiac muscle), both involuntary.
3. Beating of the heart: Cardiac muscle, which is involuntary.
4. Making of faces: Involves skeletal muscles, which are under voluntary control (we can consciously control facial expressions).

Answer:

D. making of faces