What are three characteristics of muscle you can observe under microscope?

Striations: Sarcomeres, the repeating units of muscle fibers, are visible under a microscope as alternating dark and light bands, which create a striated or striped appearance.

Myofilaments: Within sarcomeres, you can observe thin filaments, composed primarily of actin proteins, and thick filaments, composed mainly of myosin proteins. These myofilaments slide past each other during muscle contraction and relaxation.

Z-disks and M-lines: Z-disks are structures that mark the boundaries of sarcomeres, while M-lines are located in the middle of sarcomeres and help stabilize the thick filaments.