Question

multiple choice question
in what type of chordate is the spinal cord surrounded by a backbone composed of cartilage or bone?
o vertebrates
o urochordates
o lancelets
o hagfishes

Explanation:

Vertebrates are a type of chordate. A key characteristic of vertebrates is that they have a spinal cord surrounded by a backbone (vertebral column) which can be composed of cartilage (e.g., in some fish like sharks) or bone (e.g., in most higher vertebrates like mammals, birds, reptiles). Urochordates (tunicates) have a notochord only in the larval stage. Lancelets have a notochord that extends the length of their body but no true backbone. Hagfishes are invertebrates (although they are in the craniate group, they lack a true backbone).

Answer:

vertebrates