Question

earthworms are in the phylum annelida and have a closed circulatory system. earthworms are in which class within the phylum annelida? class oligochaeta class hirudinea

Explanation:

Earthworms belong to Phylum Annelida. Class Oligochaeta includes earthworms, which have a closed circulatory system and are characterized by few setae (bristles) on their segments. Class Hirudinea includes leeches, not earthworms. So the correct class for earthworms is Class Oligochaeta.

Answer:

A. Class Oligochaeta