Answer:
somites
Step-by-step explanation:
Embryonic development looks like a chronometer. Next to the future spine, cells are differentiated with a certain spacing that scientists call "somites." These are structures that grow, change shape. Somites will give rise to vertebrae, ribs, and axial musculature.
Somites are transient epithelial structures. These structures form early in embryonic development and originate with other important structures in the vertebrate organism.