As you bend your arm up to take a drink, the ________ muscles are active, and when you extend your arm to put the glass down, the ________ muscles are active.
A) striated; smooth
B) flexor; extensor
C) extensor; flexor
D) Type II; Type I

Question

Quizplus · Accepted Answer

The muscles responsible for bending the arm are the flexor muscles, while the muscles responsible for extending the arm are the extensor muscles. Therefore, the best choice is B, which identifies the two muscle types involved in these actions.

As You Bend Your Arm Up to Take a Drink