Echinoderms use pheromones to communicate with each other.
Starfish and sea urchins are also echinoderms.
Starfish use pheromones to communicate with each other.
what uses pheromones to communicate with each other?
Options:
  - starfish
  - bees
  - bacteria
  - honeybees
  - density
  - humans
  - h2o
  - insects