Final answer:
The non-dorsal mesoderm develops into various connective tissues of the animal body, such as the ribs, lungs, segmental muscle, and the notochord.
Step-by-step explanation:
The non-dorsal mesoderm refers to the mesoderm that is located on either side of the vertebrate neural tube but does not develop into dorsal structures. Instead, it develops into various connective tissues of the animal body, such as the ribs, lungs, segmental muscle, and the notochord. The notochord is a rod-shaped structure that forms the central axis of the animal body.