Tunicates are invertebrate marine animals also known as which of the following?

• A. Vertebrates
• B. Urochordates
• C. Echinoderms
• D. Crustaceans

Answer: (B)

Tunicates are invertebrate marine animals and belong to the group called urochordates. They are considered chordates because, in their larval stage, they show key chordate features such as a notochord and a dorsal nerve cord, along with pharyngeal slits. However, as adults they typically lose these features and do not have a vertebral column, which is why they are not vertebrates. The other groups listed are distinct phyla: vertebrates have backbones, echinoderms include animals like starfish with radial symmetry as adults, and crustaceans are arthropods such as crabs and lobsters. Therefore, the term urochordates best describes tunicates.