Embryonic development can be divided into several key stages: 1. Fertilization: The process where a sperm cell merges with an egg cell to form a zygote. 2. Cleavage: Rapid cell division of the zygote without growth, resulting in a multicellular structure called a morula. 3. Blastulation: The formation of a blastula, a hollow ball of cells with an inner cell mass that will eventually develop into the embryo. 4. Gastrulation: The process where the blastula reorganizes into a three-layered structure called the gastrula, consisting of the ectoderm, mesoderm, and endoderm. 5. Organogenesis: The formation of organs from the three germ layers.
