HOSA Human Growth And Development Practice Test

The blastocyst stage follows the morula in embryonic development. After the fertilization of the egg, the zygote is formed, which begins to divide as it travels down the fallopian tube. The morula, a solid ball of cells, forms after several divisions. As cell division continues, the morula transforms into the blastocyst, which is a hollow structure containing an inner cell mass that will eventually develop into the embryo and an outer layer that will become part of the placenta. This transition from morula to blastocyst is a critical step in the development process, as it prepares the embryo for implantation in the uterine lining. The other stages listed, such as the zygote, fetal, and implantation stages, occur either prior to this point or represent different stages of development that do not directly follow the morula.