Embryology is the branch of biology that studies the development of embryos from fertilization to the fetal stage. It explores how a single fertilized egg, or zygote, undergoes numerous cell divisions and differentiations to form various tissues and organs. This process is crucial for understanding how complex organisms develop and grow. Researchers in embryology examine various stages of development, including cleavage, gastrulation, and organogenesis. By studying these stages, scientists can gain insights into developmental disorders and improve techniques in areas like reproductive medicine and stem cell research. Understanding embryonic development is essential for advancements in health and medicine.