Embryogenesis is the process by which a fertilized egg develops into a fully formed embryo. It begins with the union of a sperm and an egg, forming a zygote. This zygote undergoes multiple rounds of cell division, leading to the formation of a blastocyst, which eventually implants into the uterus in mammals. During embryogenesis, cells differentiate into various types, forming the basic structures of the organism. This process involves several stages, including cleavage, gastrulation, and organogenesis, each critical for proper development. The entire process is tightly regulated by genetic and environmental factors to ensure healthy growth.