In a specimen-based viva, the examiner describes this case: a museum practical asks students to compare sponges, cnidarians, flatworms, molluscs, annelids, arthropods, and echinoderms. Choose the concept that fits it best.

Studying representative phyla helps students compare major invertebrate body plans, levels of organization, symmetry, body cavities, feeding modes, locomotion, and evolutionary relationships. This MCQ belongs to the Practical zoology topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.