There is of course lot's of descriptions in biology books, this is a nice summary of the basics: https://www.khanacademy.org/science/biology/developmental-biolo

There is of course lot's of descriptions in biology books, this is a nice summary of the basics: https://www.khanacademy.org/science/biology/developmental-biology/signaling-and-transcription-factors-in-development/a/frog-development-examples https://www.khanacademy.org/science/biology/developmental-bi...