What is the name of dark band in a sarcomere that shows the section of the sarcomere that contains myosin filaments?

The dark band in a sarcomere that contains myosin filaments is known as the A band. The A band is one of the key structural features of a sarcomere, which is the basic unit of muscle contraction in striated muscle tissue. It appears dark under a microscope due to the presence of thick myosin filaments, and it remains constant in length during muscle contraction. In contrast to the A band, the light band, known as the I band, contains only actin filaments and changes in width during contraction. The interplay between these bands facilitates muscle contraction through the sliding filament mechanism.