Compared to when he was a young man, Chris's muscles ______ now that he has grown old.
A) contain fibers that are more angular than round
B) show a more even distribution of slow- and fast-twitch fibers
C) are more likely to be hybrids of fast- and slow-twitch fibers
D) are more likely to be made up of slow-twitch fibers

Question

Quizplus · Accepted Answer

As people age, their muscles are more likely to contain hybrid fibers, which are a combination of fast- and slow-twitch muscle fibers. This change can occur due to alterations in physical activity levels and the body's adaptation to aging.

Compared to When He Was a Young Man, Chris's Muscles