25
When a physician elicits the knee-jerk reflex by tapping deep tendons in the knee, the normal response is for the leer leg to swing forward. When this happens:
Correct Answer:A
Explanation:
The knee-jerk reflex involves quadriceps (front thigh) contraction and hamstring (back thigh) relaxation.
26
The diagram shows some of the muscles and bones of the human arm. When muscle X contracts, what happens to the arm and what happens to muscle Y?
Correct Answer:C
Explanation:
If muscle X is the biceps (flexor), contraction bends the arm while the triceps (extensor) relaxes.
27
Bones of the skull are joined by:
Correct Answer:A
Explanation:
Skull bones are fused by fixed joints (sutures).
28
The muscles attached to the bones are:
Correct Answer:C
Explanation:
Skeletal muscles are voluntary and striated.