Question

At approximately what stage is the embryo termed a morula?

Options

• 8–16 cell stage

• 2–4 cell stage

• 1-cell stage

• ~64 cell stage with a blastocoel

Answer 1

The morula stage is designated when the embryo contains 8–16 blastomeres. It has a solid, berry-shaped appearance resembling a mulberry. The morula continues to divide and eventually transforms into a blastocyst as it moves further into the uterus during the process called blastulation.