Embryo

An embryo is an early stage of development for a living organism, particularly in humans and many animals. It begins when a sperm fertilizes an egg, forming a single cell that divides and grows into a complex structure. In humans, the embryonic stage lasts from conception up to about eight weeks of development, during which essential organs and body parts begin to form. After this period, the embryo is referred to as a fetus. The study of embryos is important in biology, medicine, and reproductive science, as it helps us understand development and potential congenital issues.