Which body part represents the notochord in vertebrates?

Notochod changes into Vertebral Column in the the vertebrates! It can be bony or cartilagenous!

So the answer is Vertebral Column!

Vertebral column

Explanation:

The notochord is the flexible long rod-like structure. It makes the endoskeleton of chordate's embryo. In vertebrates, the notochord serves as an axis for the formation of vertebral column or spine around it.

The transformation of notochord into the vertebral column in vertebrates occurs during embryonic development. The function of both notochord and vertebral column is to give mechanical strength and support to the body.