Question

question 8 of 10
how does pregnancy begin?
a. a placenta forms in the uterus.
b. contractions begin in the uterine wall.
c. the blastocyst differentiates into two cell types.
d. a sperm reaches an egg in the fallopian tube.

Explanation:

Pregnancy begins with fertilization, which occurs when a sperm cell successfully reaches and fuses with an egg cell in the fallopian tube. The formation of the placenta, uterine contractions, and blastocyst - cell differentiation are later events in pregnancy.

Answer:

D. A sperm reaches an egg in the fallopian tube.