Symmetry about a central axis.

• A. Radial symmetry
• B. Bilateral symmetry
• C. Asymmetry
• D. Spiral symmetry

Answer: (A)

Radial symmetry is when an organism’s body parts are arranged around a central axis, so any plane that passes through the center can divide the body into similar halves. This means you can cut through the center in many different directions and still get mirror-image or nearly identical sections. That flexibility around the center is exactly what “symmetry about a central axis” describes. Organisms like jellyfish, sea urchins, and starfish exhibit this layout, reflecting parts radiating outward from a central point. In contrast, bilateral symmetry has a single plane of symmetry (left vs right), asymmetry has no symmetry, and spiral symmetry involves a spiral arrangement rather than symmetry about a central axis.