The excretory organ of an earthworm is called ...

Explanation

Earthworms are invertebrates that belong to the phylum Annelida. They are known to possess an excretory system that helps in removing waste materials from their body. The excretory organ of an earthworm is called nephridia. Nephridia are tiny, coiled tubes that are found in pairs in each segment of an earthworm's body. They are responsible for filtering waste products such as excess water, salts, and nitrogenous waste from the blood. These waste products are then excreted out of the body through tiny pores called nephridiopores present on the surface of the worm's body. Flame cells are found in the excretory system of flatworms, while malphiligan tubules are found in insects like grasshoppers, and chloragogenus cells are found in the body cavity of some invertebrates like annelids and arthropods. Kidneys are the excretory organs found in vertebrates, including humans. Therefore, the correct answer to this question is Option A: nephridia.