A medical diagnostic procedure, used by physicians to identify hereditary defects before an infant's birth that draws fluid from the sac surrounding the fetus, is called:
amniocentesis
ultrasonography
chorionic villus biopsy
fetoscopy
How do gametes differ from other cells in the body?
Contain no chromatids
Contain one half the number of chromosomes that other cells have.
Contain twice the number of genes that other cells have.
Contain thrice the number of genes that other cells have.
The prenatal development of the organs of the fetus assume their specialized functions during the :
germinal stage
embryonic stage
fetal stage
critical stage
The primary female reproductive organs, the ovaries, produce mature ova and the female sex hormones:
estrogen and testosterone
estrogen and progesterone
progesterone and testosterone
androsterone and progesterone
Sperm are produced in the man's body in winding tubules within the:
epididymis
urethra
testes
fallopian tubes
About what percent of zygotes die shortly after fertilization?
10 percent
23 percent
33 percent
43 percent
As a result of cleavage, the zygote becomes transformed into a hollow ball of cells called the:
mitosis
blastocyst
chorion
ectoderm
If unfertilized, the ovum degenerates after about how much time?
24 hours
5 days
14 days
28 days
The principal male sex hormones are:
estrogen and progesterone.
estrogen and testosterone.
testosterone and androsterone.
testosterone and semen.
The principle that describes development as starting with the head and brain areas and moving downward is called:
cephalocaudal development
proximodistal development
teratology development
progressive development
