Must produce chorionic gonadotropin to maintain endometrium. Week 3 - 3 cell layers, yolk sac absorption, heart tubes and neural tube begin to form. Week 4 - neural tube closes, heart beat begins, limb buds form, embryo curls up somewhat. Week 5 - head features form, limbs continue to form. End of embryonic stage.
Cloning is the process of creating identical individuals.
Armadillos usually produce a clone of 4 identical offspring. Although people have been able for some time to separate the cells of a fertilized egg at, say, the 8-cell stage, and grow each into a new organism, only recently have people been able to clone from the cells of an adult mammal. This is generally done by taking cells from an adult, starving the cells, removing the nucleus with a very fine tube, and replacing the nucleus of a fertilized egg with the nucleus from the adult animal. The success rate for this type of cloning is still quite low. Cloning an adult human would result in another adult no more like the original than identical twins who have been raised apart from each other.