What adaptations to life in the soil do the animals living in it have? Describe the conditions of existence and adaptation to them in the earthworm

The skin is covered with mucus, which reduces friction, facilitates breathing, the presence of bristles on the ventral side, helps to move, the presence of ring and longitudinal muscles, which allows the front end to be thin with the help of ring muscles and squeeze into the cracks in the soil, fixing with bristles, pulling the rear end, thickening, moving forward. If necessary, in dense soil, he eats his way, passing the soil through the digestive tract