Why is the earthworm similar to the ragworm?

The earthworm and the ragworm are similar in that they both belong to the class Oligochaeta (earthworms) and Polychaeta (ragworms), respectively, and share a segmented body structure. Both types of worms play essential roles in their ecosystems, contributing to soil aeration and nutrient cycling. Additionally, they exhibit similar physiological traits, such as a coelom and a robust muscular system that aids in movement through their respective environments. Despite their differences in habitat and classification, they share fundamental biological characteristics that highlight their evolutionary connection.