Which term refers to the subphylum that includes lobsters and shrimps?

• A. Chitin
• B. Crustacea
• C. Cetacea
• D. Cnidaria

Answer: (B)

Crustacea. Lobsters and shrimps are crustaceans, a subphylum of arthropods. Crustaceans are mainly aquatic and share features such as a hard exoskeleton (often reinforced with minerals), jointed limbs, and two pairs of antennae. Many crustaceans have a front body region (cephalon) with a thorax and abdomen, and the familiar decapods like lobsters and shrimps have ten legs, with the first pair often adapted as claws. This combination of traits makes Crustacea the correct term for the group that includes lobsters and shrimps.

Chitin is a structural carbohydrate in exoskeletons, not a taxonomic group. Cetacea are whales (mammals), and Cnidaria includes jellyfish and corals with radial symmetry.