The placenta is the organ that:
transfers maternal nutrients to the fetus.
protects the fetus against infectious organisms.
directly connects the fetal and maternal blood supplies.
connects the embryo to the vaginal wall.
During menstrual flow, what body structure secretes hormones into the bloodstream to "direct" another ovarian follicle to begin rapid growth?
Ovary
Pituitary gland
Uterus
Thyroid gland
The principal male sex hormones are:
estrogen and progesterone.
estrogen and testosterone.
testosterone and androsterone.
testosterone and semen.
Sex cells (sperm and ova) are called:
alleles
genes
gametes
zygotes
If unfertilized, the ovum degenerates after about how much time?
24 hours
5 days
14 days
28 days
As a result of cleavage, the zygote becomes transformed into a hollow ball of cells called the:
mitosis
blastocyst
chorion
ectoderm
About what percent of zygotes die shortly after fertilization?
10 percent
23 percent
33 percent
43 percent
What is puberty?
Partitioning of replicated chromosomes into two identical groups.
Prenatal development of the organs of the fetus.
Adults undergo the process of sexual maturation.
Reproductive cycle in the female primates.
During ejaculation, as the sperm pass out of the man's body through the penis, secretions that fuel and protect the sperm are also released from the:
Seminal vesicles and prostate gland
Androgens and prostate gland
Prostate gland and urethra
Seminal vesicles and urethra
Long, threadlike structures made of protein and nucleic acid containing hereditary materials are known as :
genomes
chromosomes
DNA
