Question

lo 4.3. what are the two main types of muscle fibers?
type a and type b fibers
thin and thick fibers
smooth and striated fibers
slow - twitch (type i) and fast - twitch (type ii) fibers.
red and white fibers

Explanation:

Muscle fibers are mainly classified as slow - twitch (Type I) which are fatigue - resistant and used for endurance activities, and fast - twitch (Type II) which generate more power but fatigue quickly.

Answer:

D. Slow - twitch (Type I) and fast - twitch (Type II) fibers