Developmental Mechanisms Problem Set

Problem 3: Transition to a 2- or 3-layered embryo


At what stage of animal development do cells first move from the surface of the embryo into the interior, resulting in a two- or three-layered embryo?

A. zygote formation
B. blastulation
C. neurulation
D. gastrulation
Gastrulation begins when the wall of the single-layered blastula begins to invaginate. This invagination, and the subsequent rearrangement of cells creates a multi-layered embryo.
E. metamorphosis

The Biology Project
Department of Biochemistry and Molecular Biophysics
The University of Arizona
Thursday, October 30, 1997
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