Which of the following is NOT characteristic of cnidarians?

A) They are mostly marine.
B) They have radial symmetry.
C) They have one body shape, known as medusa.
D) They have cells that contain stinging organelles.
E) There is only one opening into the gastrovascular cavity.

Medusa

A free-swimming or floating stage in the life cycle of some cnidarians, typically having a bell-shaped body and tentacles.

Cnidarians

Phylum of animals that have stinging cells called cnidocytes, two tissue layers, and radial symmetry; include hydras and jellyfish.

Gastrovascular Cavity

A central digestive cavity with a single opening that functions as both mouth and anus; characteristic of cnidarians and flatworms.