1. The uterus at the time of fertilization is beautifully adapted to receive the developing embryo, providing it with food and disposing of its wastes.
2. A few days prior to this time, the uterus was small, its tissues were thin, and its supply of blood vessels was poor.
3. When the fertilized egg or zygote is about to enter the uterus become much larger, its inner wall becomes thick, soft and moist with fluid, its blood supply is greatly increased and waiting for an embryonic occupant.