You are presented with the quiz "What do echinoderms employ to grip surfaces?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "echinoderms use pheromones to communicate with each other" and "echinoderms and molluscs use adhesives to grip the substrate during locomotion". 

So, what's the best answer to the question?


 

 adhesives          