21.The child will be a female if the man's X chromosome combines with the woman's:
a.X chromosome.
b.Y chromosome.
c.two Y chromosomes.
d.X and Y chromosomes.
22.The child will be a male if the woman's X chromosome combines with the man's:
a.X chromosome.
b.Y chromosome.
c.two Y chromosomes.
d.two X chromosomes.
23.Basically, the sex of a child is determined by:
a.Müllerian-inhibiting substances.
b.the male's Y chromosome.
c.hormones secreted by glands.
d.the woman's X chromosome.
24.In order for a male to be produced, the primitive gonad must develop into:
a.chromosomes.
b.testes.
c.testosterone.
d.hormones.
25.The hormone that spurs development of testes is called:
a.progesterone.
b.Müllerian-inhibiting substance.
c.testosterone.
d.estrogen.
26.Reproductive hormones start to work by the time the embryo is:
a.three days old.
b.eight days old.
c.two weeks old.
d.a month old.
27.Reproductive hormones start to work when the embryo is about _______ millimeters long.
a.two
b.four
c.six
d.eight
28.By the end of the eighth to twelfth week, the child's sex can be determined by:
a.fetal movements.
b.tissue plasticity.
c.progesterone production.
d.external genitalia.
29.The female hormone that affects female characteristics like breast and hip size is called:
a.androgen.
b.progesterone.
c.estrogen.
d.Müllerian-inhibiting substance.
30.The complicated process that leads to first menstruation is triggered by:
a.progesterone and Müllerian-inhibiting substance.
b.estrogen and progesterone.
c.testosterone and Müllerian-inhibiting substance.
d.estrogen and Müllerian-inhibiting substance.