Why do earthworms have moist skin?
Earthworms have a special skin that allows them to “breathe” oxygen right through it. Earthworms have moist skin because it is necessary for oxygen to be absorbed and carbon dioxide to be given off. The worm’s skin is protected by a thin cuticle and kept moist by a slimy mucus. This lets it absorb the oxygen it needs and expel carbon dioxide. If a worm is dried up by the sun, it will die because the exchange of gases can’t take place.