What type of body symmetry do nematodes possess?

• A. Bilateral
• B. Radial
• C. Asymmetrical
• D. Pentaradial

Answer: (A)

Bilateral symmetry means the body has left and right halves that are mirror images along a single plane that runs from front to back. Nematodes fit this pattern because they are elongated, taper at both ends, and have a distinct front (head) region, back (tail), and a directional orientation (dorsal vs. ventral). This single plane of symmetry supports their forward, coordinated movement and organized body plan.

Radial symmetry, with multiple planes of division around a central axis, is typical of jellyfish and sea urchins. Asymmetry means no consistent plane of symmetry, seen in some sponges. Pentaradial symmetry is a fivefold arrangement found in many echinoderms like starfish. Since nematodes align with a left-right mirror image along one plane, bilateral symmetry is the best description.