A zygote is the initial cell formed when two gamete cells, typically an egg (from the female) and a sperm (from the male), fuse during fertilization.
It represents the earliest stage of development in sexually reproducing organisms.
The zygote contains all the genetic information needed to create a new individual and undergoes rapid cell division, eventually developing into an embryo.
As the embryo continues to grow and divide, it eventually forms the complex tissues and structures that make up a fully developed organism. In humans, the zygote is the starting point of prenatal development.