What is the term for the process by which the ectoderm, endoderm, and mesoderm develop into internal organs?

The correct term for the process by which the ectoderm, endoderm, and mesoderm develop into internal organs is organogenesis. This is a key phase in embryonic development where the three primary germ layers differentiate and form the various organs and tissues of the body.

During organogenesis, cells in each germ layer take on specific identities and functions. For instance, the endoderm primarily gives rise to the gastrointestinal tract and associated organs such as the liver and pancreas, while the mesoderm develops into structures such as muscles, the skeleton, and the cardiovascular system. The ectoderm, on the other hand, will form the nervous system and the outer layer of the skin.

Each of the other choices represents different biological processes. Neurogenesis specifically refers to the formation of nerve cells from neural stem or progenitor cells. Gametogenesis is the process of forming gametes, such as sperm and eggs, through meiosis. Fertilization is the union of sperm and egg, leading to the formation of a zygote. Understanding these distinctions highlights the specific role of organogenesis in terms of organ development and overall embryonic growth.