Embryology is the branch of biology that studies the development of embryos from fertilization to the fetal stage. It examines how a single fertilized egg, or zygote, divides and differentiates into various cell types, forming the structures of a new organism. This process involves several stages, including cleavage, gastrulation, and organogenesis. Researchers in embryology explore the genetic and environmental factors that influence development. Understanding these processes is crucial for fields like medicine, where knowledge of embryonic development can help address congenital disorders and improve reproductive technologies, such as in vitro fertilization.