Which statement best describes crustaceans based on common examples?

• A. They include animals such as lobster and crab.
• B. They are a type of insect.
• C. They exclusively respire through lungs.
• D. They lack excretory systems.

Answer: (A)

Crustaceans are a group of arthropods that includes familiar creatures like lobster and crab. Seeing these examples helps solidify what crustaceans are, since they’re defined by features such as a hard exoskeleton and multiple jointed limbs, with many species living in water. They’re not insects, which belong to a different arthropod group with a distinct body plan and often wings. Crustaceans typically breathe with gills rather than lungs, though some gas exchange can occur across body surfaces. They also have excretory organs, such as antennal glands, so the idea that they lack excretory systems isn’t correct. In short, lobster and crab are classic crustaceans, which is why that statement best describes the group.