Future embryos are the early stages of development in a living organism. They are formed when an ovum (OVA) is fertilized by a sperm cell, resulting in a zygote. The zygote then divides and develops into an embryo, which is composed of two layers: the inner layer, or yolk (YOLKS), and the outer layer, or trophoblast. The yolk provides nutrition to the developing embryo, while the trophoblast forms the placenta and other structures that will eventually become the fetus.