Fertilization of the human ovum normally

A. False It occurs in the outer third of the uterine tube.

B. True The zona pellucida becomes impermeable.

C. False The ovum remains viable for only about a day.

D. True During this time the fertilized ovum travels along the uterine tube and spends several days free in the uterus.

E. True This is necessary to maintain ovarian hormone production whose withdrawal causes endometrial necrosis.