In a specimen-based viva, the examiner describes this case: a planarian has a definite head end and can be divided into right and left mirror halves. Choose the concept that fits it best.

Correct Answer: D

bilateral symmetry

Flatworms show bilateral symmetry and cephalization. This organization is linked with directional movement and concentration of sensory structures at the anterior end. This MCQ belongs to the Platyhelminthes topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.