Why are Echinoderms considered to be closely?

Echinoderms are considered closely related to chordates due to their shared developmental features, such as the presence of a deuterostome developmental pattern, where the anus forms before the mouth during embryonic development. Additionally, both groups exhibit similarities in their genetic and molecular structures, particularly in their Hox gene arrangements. These characteristics suggest a common evolutionary ancestor, highlighting the evolutionary connection between echinoderms and chordates.