When a sperm and an egg combine, a zygote is first formed as a single cell structure. The baby's sex and genetic composition are already determined at this point.
The zygote's cell divides repeatedly until it finally forms the blastocyst, a hollow ball of cells. Before implanting in the inner lining of their uterine wall, the blastocyst resides in their uterus for a few days (endometrium). It continues to produce new cells that divide into layers.
when you are four weeks pregnant with your baby. The fertilized egg, also known as a blastocyst, begins to divide itself at the time of conception. It will have 200 cells and be roughly 4-5 mm across by the end of this week.
To know more about zygote visit:-
https://brainly.com/question/29769026
#SPJ1