Fact 1: Adult echinoderms have radial symmetry.

Fact 2: Modern echinoderms include starfish and sea urchins.

Given the two facts above, answer the question "What has radial symmetry?" with the following options: 
- sea urchins
 - A Greek letter
 - humans
 - Most plants
 - peachleaf willow
 - catfish
 - gastropod shells
 - ducks


 

 sea urchins        