What happens during embryonic stem cell? Look carefully at the diagram then explain what is happening during it. (DIFFICULT)

A sperm cell meets a human egg. Then, a sperm fertilises the egg to form a fertilised zygote or egg with a full set of human chromosomes, which is 46. Then, the zygote starts dividing by mitosis to form an embryo. None of the cells would have specialised as undifferentiated cells. They have the choice to become any cell type e.g nerve cells, brain cell or muscle cells. The cell then undergoes its first wave of differentiation to form two cell types in a structure called the blastocyst.