Gastrulation is the stage in the early embryonic development of most animals, during which the blastula is reorganized into a multilayered structure known as the gastrula.

What do u mean by gastrulation?

In developmental biology, gastrulation is a phase early in the embryonic development of most animals, during which the blastula (a single-layered hollow sphere of cells) is reorganized into a multilayered structure known as the gastrula.

What does involution mean?

1a : an inward curvature or penetration. b : the formation of a gastrula by ingrowth of cells formed at the dorsal lip. 2 : a shrinking or return to a former size involution of the uterus after pregnancy.