<prompt> Which of the following decreases in length during the contraction of a skeletal muscle fiber?A band of the sarcomereI band of the sarcomereThick filamentsThin filaments  <response>: The physical lengths of the actin and myosin filaments do not change during contraction. Therefore, the A band, which is composed of myosin filaments, does not change either. The distance between Z disks decreases, but the Z disks themselves do not change. Only the I band decreases in length as the muscle contracts. 