Crustaceans are defined as what?

Crustaceans are defined as what?

• A. Mammals with fur that live in water.
• B. Birds adapted to water for flight.
• C. They have a hard exoskeleton.
• D. A group of aquatic animals with a hard exoskeleton, such as crabs and shrimp.

Answer: (D)

Crustaceans are a group of aquatic arthropods that typically have a hard exoskeleton made of chitin, which provides protection and support. They grow by molting this outer shell, and they possess jointed limbs. The best description here captures both the group and a representative example: they are aquatic animals with a hard exoskeleton, such as crabs and shrimp. This combines the defining protective covering with the common aquatic lifestyle and names examples that clearly belong to crustaceans. The other options refer to mammals or birds, or only mention a single feature without identifying the crustacean group.