Question 15 (1 point) During contraction, disappears as actin and myosin filaments overlap: A. M \( \begin{array}{l}\text { zone } \\ \begin{array}{ll}\text { A) Hzone } \\ \text { B) I zone } \\ \text { C) z-line } \\ \text { (D) cross bridge }\end{array}\end{array} \)

When muscles contract, the H zone actually disappears as the actin and myosin filaments slide past each other. This is because the H zone is the area in the sarcomere where only myosin filaments are present, and it gets "filled in" when the actin overlaps during contraction. To visualize this, think of your muscle fibers as a well-organized dance group. When they start dancing (contracting), their movements overlap, and areas of space (like the H zone) where there was no interaction get filled with the rhythm of their movements. So, in this dance, it's all about the overlap!