Crustaceans have a hard external skeleton composed of chitin, which helps to protect their soft internal organs. The other options do not accurately describe crustaceans- radial body symmetry is more characteristic of echinoderms (such as starfish), nautilus and squid are mollusks, and spiders and scorpions are in a separate arachnid group.

Solved

Crustaceans

Question 136

Multiple Choice

Crustaceans:

A) have radial body symmetry.
B) include animals such as the nautilus and squid.
C) include animals such as spiders and scorpions.
D) have a hard external skeleton composed of chitin.

Correct Answer: