Step-by-step explanation:
The highest rate of cell division is a human embryo. Once the sperm finds a viable egg in fallopian tube, it travels to the uterus. Attaches to the uterus where it is called a zygote then begins to multiply rapidly, along with the placenta (from which the developing embryo gets o2, food source, all nutrients a fetus needs to grow,to develop the unborn fetus..
hope this helps..