Question

which region of the sarcomere does not change length between muscle relaxation and muscle contraction? multiple choice h zone a band i band z disc

Explanation:

The A - band of the sarcomere contains thick filaments (myosin) and its length remains constant during muscle contraction and relaxation. The H - zone shortens during contraction as thin filaments (actin) slide over thick filaments. The I - band also shortens as the Z - discs move closer together. The Z - disc is a structure and not a region that changes length in the context of contraction/relaxation in the way the others do.

Answer:

B. A band