Here's a breakdown:
* Zygote: The very first cell formed from the fusion of an egg and sperm.
* Cleavage: The process of rapid cell division in the zygote, without increasing the overall size of the embryo.
* Morula: The solid ball of cells formed after several rounds of cleavage.
* Blastocyst: The morula develops into a blastocyst, which is a hollow ball of cells with an inner cell mass.
The morula is a crucial stage in early embryonic development, marking the transition from a single-celled zygote to a multicellular structure.
