Name the excretory organ present in earthworm through which excretion takes place?

Earthworms have slightly more evolved excretory structures called nephridia. A pair of nephridia is present on each segment of the earthworm. They are similar to flame cells in that they have a tubule with cilia. Excretion occurs through a pore called the nephridiopore.

They have moist skin because it is necessary for oxygen to be absorbed and carbon dioxide to be given off. The Earth 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.