Final answer:
Notochords are more closely related to echinoderms than to other invertebrates due to shared embryonic development patterns since both are deuterostomes.The correct answer to the student's question is b) Shared embryonic development patterns.
Step-by-step explanation:
The reason notochords are more closely related to echinoderms than to other invertebrates is due to shared embryonic development patterns, specifically, both chordates (which include animals with notochords) and echinoderms are deuterostomes.
This is a critical distinction in the animal kingdom and refers to the developmental sequence of the embryo, where the anus forms before the mouth. This is opposite to the developmental pattern of protostomes, a group that encompasses other invertebrates like mollusks, annelids, and arthropods. Furthermore, deuterostomes share similar patterns of early development, such as a tripartite coelom and pharyngeal slits during certain stages, which contributes to this close relationship.
Chordates and echinoderms also share certain features like a coelom, and despite echinoderms exhibiting pentaradial symmetry as adults, they possess bilateral symmetry in their larval stages, a characteristic also seen in chordates. Additional commonalities include the presence of an endoskeleton developed by epidermal cells. All of these factors, rather than body symmetry, digestive system features, or habitat preferences, indicate a closer evolutionary relationship between chordates and echinoderms.
The correct answer to the student's question is b) Shared embryonic development patterns.