Changes in Cell Position Occur Extensively During Which of the Following

Question

Changes in cell position occur extensively during which of the following?
A) cleavage, but not during gastrulation or organogenesis
B) gastrulation and cleavage
C) gastrulation
D) fertilization and cleavage, but not during gastrulation
E) organogenesis, but not during gastrulation or cleavage

Accepted Answer

Changes in cell position mainly occur during gastrulation, when the three germ layers (endoderm, mesoderm, and ectoderm) are formed and the basic body plan is established. Although some changes in cell position occur during fertilization and cleavage, they are mostly due to cell division rather than cell migration. Changes in cell position also occur during organogenesis, but to a lesser extent than during gastrulation. Therefore, choice C is the best answer.