A．The sheep was chosen as an ideal subject because of its genetic development, not for its precedence as a research subject.
B．The human embryo comes to rely upon its own genetic code at an earlier stage of development than the mice embryo.
C．The unfertilized sheep egg acquires a limitless supply of protein from the mother’’ s ovary.
D．The earlier the foreign nucleus assumes genetic control of the embryo, the more successful it will likely be.
E．The foreign nucleus transplanted to an embryo may be consider "older" than the nucleus it replaced.