Epiboly is the process of

Options

A. Mass migration of cells from the animal hemisphere so that upper micromeres begin to migrate over the edge of the dorsal lip and roll inside and are tucked beneath the outer layer
B. Overgrowth when the micromeres divide rapidly and begin to spread downwards over the megameres except at the yolk plug
C. Rotation of gastrula within the vitelline membrane so that the animal pole becomes anterior
D. Formation of a small slit like invagination occurring on the grey crescent

Answer

B

Explanation

Epiboly occurs in the prospective ectodermal blastomeres which have an inherent property of flattening and forming an epithelial layer. Thus it involves over growth when the micromeres divide rapidly and begin to spread downwards over the megameres except yolk plug.