Question

the boundaries between adjacent sarcomeres are marked by:
a m lines
b h bands
c i bands
d a bands
e z lines

Explanation:

Sarcomeres are the basic contractile units of muscle fibers. Z - lines are the structures that separate one sarcomere from the next. M - lines are in the middle of the sarcomere (in the A - band) and are related to the organization of thick filaments. H - bands are regions in the A - band that only contain thick filaments (in relaxed muscle). I - bands are regions that only contain thin filaments. A - bands contain both thick and thin filaments (the length of the thick filament).

Answer:

E. Z lines