You are presented with the question "Where does a starfish have its water vascular system?" and the following answer choices: 
- salt and water.
 - Chlorophyll
 - the environment
 - in its arms
 - on the rocks
 - in its eyes
 - Epidermis
 - in the ocean

Now knowing that echinoderms have a unique water vascular system with tube feet and each starfish arm is lined with tube feet, choose the best answer.


 

    in its arms     