A sea star and a chordate are discussed together in a phylogeny lecture even though one is an invertebrate. In an exam answer, the key reason is: (280)

Correct Answer: C

deuterostome development

Echinoderms and chordates are deuterostomes. Their embryological characters link them despite very different adult body forms. This question is designed as a comparison-based item to reduce thin-content style repetition and improve conceptual depth.