Pre-Embryonic Development
We had said in the starting of the unit that prenatal development can be divided into two phases, embryonic and foetal. The embryonic phase of development is stated to really start from the second week after fertilization; and then lasts up to 8 weeks of the 1st trimester. In this section we describe the pre-embryo stage starting along with the events that take place at fertilization and after that proceed to explain the development of the pre-embryo up to two weeks of development.