Plan of the body in cross-section. The systems in the body are arranged in a certain way which is the same in all animals which have a backbone. The plan of the bony skeleton is a central axis from which all other parts are extended. In this lies the central axis of the nervous system, from which its branches also extend.

Diagram of the Body Plan

Plan of the body in cross-section. The systems in the body are arranged in a certain way which is the…