how does a zygote become am embryo to a fetus
Zygote vs Embryo   - A zygote is the formation from the two gametes, the sex cells sperm and egg. (pronuclei). It forms in about 3 days. - An embryo has 3 main structura â¦ l parts, further developed (forms in the 2nd week after pregnancy).o the first thing that visibly happens to a zygote is that it divides by mitosis into two cells, then they divide to form a four-celled embryo, and so on. Eventually the ball of identical-looking cells hollows and acquires an axis, and differentiation begins. For more detail, see the links below.