You are presented with the question "Which of the following does not have an anterior and posterior end?" and the following answer choices: 
- Adult mammals
 - Adult reptiles
 - Adult birds
 - Adult echinoderms
 - Earth orbiting the Sun
 - an erupting volcano
 - peachleaf willow
 - sensory neurons

Now knowing that adult echinoderms have radial symmetry and animals with radial symmetry lack an anterior and posterior end, choose the best answer.


 

    Adult echinoderms     