Why is the type named Chordates? List their main features.

Chordates are a type of animal. They are characterized by the fact that in their structure there is a dorsal axial cord – the chord. It performs the function of maintaining the shape of the body. That is, it performs the function of a primitive spine. In the lancelet, the notochord is visible throughout life. But most representatives of this type lose the notochord in the early stages of embryonic development. Man also has a chord. It transforms into intervertebral discs at the end of the first trimester of intrauterine development of the body and these cells completely disappear until the age of seven.