26.The structure labeled F in the following diagram is important in
embryonic development of humans as which of the following?
Embryology: Early and General 79a. The major site of yolk storage
b. Transfer of nutrients after the uteroplacental circulation has been established
c. The origin of the ligamentum teres hepatis
d. The source of the amniotic fluid
e. The initial site of hematopoiesis
27.Monozygotic twins arise by means of which of the following?
a. Fusion of the embryonic blastomeres from two zygotes
b. Fertilization of two oocytes by two sperm
c. Fertilization of one oocyte by two sperm
d. Division of the inner cell mass (embryoblast) into two embryonic primordia
e. Extra cleavage divisions of the zygote induced by the presence of a double
chorion
(Modified, with permission, from Sweeney L. Basic Concepts in Embryology. New York, NY:
McGraw-Hill, 1998.)