Fact 1: Adult echinoderms have radial symmetry.

Fact 2: Echinoderms are spiny skinned animals found only in marine environments.

Given the two facts above, answer the question "Adult spiny skinned animals found only in marine environments have what?" with the following options: 
- sensory neurons
 - to stay warm
 - Animal survival
 - extra brains
 - aerobic capacity
 - eight eyes
 - asymmetrical axis
 - radial symmetry


 

        radial symmetry 