Fact 1: Echinoderms use pheromones to communicate with each other.

Fact 2: Echinoderms are represented by the starfish.

Given the two facts above, answer the question "Starfish use _  to communicate with each other." with the following options: 
- scattered light
 - pheromones
 - heat produced
 - sound
 - waves
 - Chemical energy
 - electricity
 - kinetic energy


 

  pheromones       