What stage immediately follows the cleavage stage in embryonic development?

The stage that immediately follows the cleavage stage in embryonic development is indeed blastulation. During the cleavage stage, the fertilized egg undergoes a series of rapid cell divisions, resulting in a multicellular structure known as the blastula.

Blastulation involves the transformation of the solid ball of cells created during cleavage into a hollow sphere. This process results in the formation of the blastocyst in mammals, which contains an inner cell mass that eventually develops into the embryo and a surrounding layer of cells that contributes to implantation and supports the embryo.

This stage is crucial as it sets the foundation for subsequent processes, particularly gastrulation, which follows blastulation and involves the rearrangement of cells to form the three primary germ layers—ectoderm, mesoderm, and endoderm. Each of these layers will eventually give rise to different tissues and organs in the developing organism.