Which term describes the largest order of aquatic mammals that includes whales and dolphins?

Which term describes the largest order of aquatic mammals that includes whales and dolphins?

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

Answer: (A)

Cetacea is the group that names the set of mammals perfectly adapted to life in water, and it specifically includes whales, dolphins, and porpoises. It’s an order within the class Mammalia, and it’s the largest grouping of aquatic mammals by the number of species. This order is split into two main subgroups: baleen whales (Mysticeti) and toothed whales (Odontoceti), reflecting different feeding adaptations. The other terms refer to different kinds of organisms: Crustacea are crustaceans, Cnidaria are jellyfish and their relatives, and Chordata is the broader phylum that includes all vertebrates, not an order of aquatic mammals.

Cetacea is the group that names the set of mammals perfectly adapted to life in water, and it specifically includes whales, dolphins, and porpoises. It’s an order within the class Mammalia, and it’s the largest grouping of aquatic mammals by the number of species. This order is split into two main subgroups: baleen whales (Mysticeti) and toothed whales (Odontoceti), reflecting different feeding adaptations. The other terms refer to different kinds of organisms: Crustacea are crustaceans, Cnidaria are jellyfish and their relatives, and Chordata is the broader phylum that includes all vertebrates, not an order of aquatic mammals.