Why do earthworms have moist skin?

The earthworm is an inhabitant of the soil. To move around in it and not get hurt, the skin must be moist. Therefore, in the skin of the earthworm, especially in the region of the girdle, there are many skin glands that secrete mucus. In addition, the worm has no respiratory organs and this is another reason why its skin must be moist, since gas exchange is only possible through wet skin. Mucus also protects the body of the earthworm from the penetration of pathogenic bacteria and microscopic fungi.