Dental Admissions Test (DAT) Practice Test

When the developing embryo has divided into 32 cells, it is called a

1. Blastula

2. Gastrula

3. Morula

4. Zygote

The correct answer is: Morula

When the developing embryo has divided into 32 cells, it is called a morula. The morula is a stage of embryonic development that occurs after the zygote (fertilized egg) undergoes several rounds of cell division, resulting in a solid ball of cells. Option A, Blastula, is incorrect because the blastula stage occurs after the morula, where the cells arrange into a hollow sphere with a fluid-filled cavity. Option B, Gastrula, is incorrect as it is a stage that follows the blastula stage, characterized by the formation of three germ layers: endoderm, mesoderm, and ectoderm. Option D, Zygote, is incorrect as the zygote is the initial cell formed by the fusion of sperm and egg, before it undergoes multiple rounds of cell division to form the morula.