Evaluate the role of HCG and progesterone produced by the placenta in pregnancy.

HCG decreases maternal metabolism, while progesterone strengthens fetal bones.

HCG triggers maternal antibodies, while progesterone initiates labor.

HCG maintains the corpus luteum, while progesterone stabilizes the uterine lining.

HCG stimulates fetal heart rate, while progesterone forms the amniotic sac.