Fact 1: Echinoderms lack respiratory and excretory systems. Fact 2: Echinoderms are represented by the starfish. Given the two facts above, starfish lack what kind of system?
Options:
[A]. respiratory.
[B]. critical organs.
[C]. alveoli.
[D]. heat or cold.
[E]. hydration.
[F]. Bodily water.
[G]. food and shelter.
[H]. frontal zones.
[A].