When the central mass of yolk restricts cleavage to the surface of the egg,and 8 rounds of mitosis without cytoplasmic division pepper the surface with nuclei that eventually are enclosed,this is ______ cleavage.
A) Radial
B) Spiral
C) Superficial
D) Trophoblastic

Question

Quizplus · Accepted Answer

This describes superficial cleavage, where the division is restricted to the surface of the egg and does not penetrate the yolk. The result is a layer of nuclei enclosed in a common cytoplasmic mass. Radial cleavage involves cleavage planes that are either parallel or perpendicular to the polar axis of the egg, while spiral cleavage involves oblique cleavage planes, and trophoblastic cleavage is specific to the development of the trophoblast in mammals.

When the Central Mass of Yolk Restricts Cleavage to the Surface