Fertilization (the fusing of male and female gametes) produces a zygote, which then develops into an embryo. The zygote divides several times before forming a ball of cells. This is called an embryo. This embryo develops the body components such as hands, legs, head, eyes, and ears in the uterus. A foetus is the stage of the embryo at which all of the body components can be identified. As a result, the zygote is generated from gametes and leads to the construction of the embryo, while the foetus is formed from the embryo and is known as a baby when it is born.