Echinoderms use pheromones to communicate with each other.
Echinoderms are represented by the starfish.
Starfish use pheromones to communicate with each other.
Starfish use _  to communicate with each other.
Options:
[a] scattered light
[b] pheromones
[c] heat produced
[d] sound
[e] waves
[f] Chemical energy
[g] electricity
[h] kinetic energy