You are presented with the question "What has radial symmetry?" and the following answer choices: 
- sea urchins
 - A Greek letter
 - humans
 - Most plants
 - peachleaf willow
 - catfish
 - gastropod shells
 - ducks

Now knowing that adult echinoderms have radial symmetry and modern echinoderms include starfish and sea urchins, choose the best answer.


 

 sea urchins        