Question

which of the following marks the boundaries of a sarcomere?
multiple choice
i bands
h bands
z discs
m lines
a bands

Explanation:

Sarcomeres are the basic contractile units of muscle fibers. Z discs are the structures that define the boundaries of a sarcomere. I bands contain only thin filaments (actin), H bands contain only thick filaments (myosin), M lines are in the center of the sarcomere (mid - H band) and are involved in holding thick filaments together, and A bands contain both thick and thin filaments (the length of the thick filament).

Answer:

Z discs