Chapter 12, Problem 15RA

In an isotonic muscle contraction,

$\begin{array}{l}\text{a}\text{. the length of the muscle remains constant}\text{.}\hfill \\ \text{b}\text{. the muscle tension remains constant}\text{.}\hfill \\ \text{c}\text{. both muscle length and tension are changed}\text{.}\hfill \\ \text{d}\text{. movement of bones does not occur}\text{.}\hfill \end{array}$