In a specimen-based viva, the examiner describes this case: a worm-like animal moves actively in one direction and has a clear anterior end. Choose the concept that fits it best.

Correct Answer: C

bilateral symmetry

Bilateral symmetry is associated with active directional movement and cephalization. It produces right and left halves and often allows development of a head region containing sensory structures. This MCQ belongs to the Animal architecture topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.