Where does fertilisation occur in human beings? How does the zygote formed eventually develop into an infant?
The zygote immediately divides into two cells; these cells then divide again and again, over the next couple of days, and the resulting cluster of cells makes its way to the uterus (womb). This cluster of cells is called the embryo. The embryo plants itself in the lining of the uterus and continues dividing its cells to make billions of new cells. It gradually develops the different body parts, such as the head, eyes, hands, legs, etc. When the embryo reaches the stage where all its body parts can be identified, it is called the foetus. The foetus, when born, is called an infant.