Slow-twitch muscle fibers are to _______ as fast-twitch muscle fibers are to _______.
A) Ia; Ib
B) IIa; Ia
C) I; IIa and IIb
D) IIb; IIa

Question

Quizplus · Accepted Answer

Slow-twitch muscle fibers are also known as type I fibers, while fast-twitch muscle fibers are classified as type II fibers. Type II fibers are further divided into IIa and IIb. Therefore, choice C correctly pairs slow-twitch muscles with type I fibers and fast-twitch muscles with both type IIa and IIb muscle fibers.

Slow-Twitch Muscle Fibers Are to _______ as Fast-Twitch Muscle Fibers