earthworm does not have limbs yet it moves about.what enables it to do so?
Answers
Answer:
by the help of setae and hydrostatic skeleton
Explanation:
The fluid is filled in body cavity (which is referred as hydrostatic skeleton) in earthworm is surrounded by layer of circular and longitudinal muscles. the locomotion in earth worm is brought by alternate contraction of these muscles. they also have bristle like setae at lower side of the body.
first of all eathworm becomes long and thin due to the contraction of circular muscles. the setae present on the lower side of anterior end comes out, anchor and hold this end firmly.
the longitudinal muscles now contract and the circular muscles relax and the body shortens, thus pulling this portion forward. then the setae of the posterior and comes out and fix the animal on the ground.
alternate contraction and relaxation of circular and longitudinal muscles, lengthens and shorten the animal respectively and help in the movement of animals in soil.