Why are echinoderms considered to be closely related to corroded?

Echinoderms, such as starfish and sea urchins, are considered closely related to chordates, including corals, due to their shared evolutionary lineage within the deuterostomes, a major group of animals characterized by specific developmental features. Both echinoderms and chordates exhibit bilateral symmetry at some stage of their development and share common genetic and embryological characteristics. Moreover, molecular studies have shown significant genetic similarities between these groups, supporting their close evolutionary relationship.