Question

A __________ is a chordate but not a vertebrate. a) lancelet b) frog c) sea star d) lamprey e) shark

Answer 1

A lancelet is a chordate but not a vertebrate because it does not have a vertebral column made of bones. It retains the four key features of chordates. Therefore, the correct option is A.

Step-by-step explanation:

Although not a vertebrate, a lancelet is a chordate. Lancelets, or amphioxi, are members of the phylum Chordata's subphylum Cephalochordata. Lancelets lack a true vertebral column or backbone, but they do have some of the characteristics of chordates, including a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-an*l tail.

This sets them apart from other vertebrates that have a vertebral column composed of vertebrae, such as sharks (option e), lampreys (option d), and frogs (option b). Sea stars (option c) are not chordates; instead, they are members of the Echinodermata phylum.

Therefore, the correct option is A.

Answer 2

A _ lancelet_ is a chordate but not a vertebrate.

How we can complete this statement?

A chordate is an animal belonging to the phylum Chordata. Chordates are characterized by the presence of a notochord, which is a flexible rod-like structure that runs along the length of the body.

In vertebrate chordates, the notochord is usually replaced by a vertebral column or backbone during development.

Lancelets are chordates but do not have a vertebral column (backbone), so they are considered non-vertebrate chordates. The other options (frog, sea star, lamprey, and shark) are vertebrates, meaning they have a backbone or vertebral column.