Circular muscles help in extension and narrowing of the body of the earthworm. When circular muscles contract the protractor muscles relax causing the retractor muscles to contract, thus withdrawing the setae.
serve to give him (or her) mobility - moving legs and such.
In smooth muscle these transitionally alternating muscle fibers help to serve the actions of peristalsis. As the circular fibers contract the tube (lumen) constricts and as the longitudinal fibers contract it opens up the lumen.
Ganglion
Seminal vesicles in earthworms store and release sperm during copulation. They play a crucial role in the reproductive process by providing a reservoir for sperm to be transferred to the female during mating.
To serve a ritual function.
How does cholesterol function
An artificial pacemaker works by detecting changes in the heart's rhythm. If it detects a 'problem' - it delivers a shock to the heart's muscle - returning the heartbeat to a regular beat.
The muscular system is a series of different muscles throughout a cows body. The muscles serve the purpose of helping the cows to move.
Egagt
By the Function they serve
The function of seeds are for the plant to reproduce.
By the Function they serve