Which of the following cannot pass across the placenta?
(a) oxygen
(b) waste materials
(c) blood
(d) nutrients

See Answers (2)

Accepted Answer

The placenta is the structure that allows for transfer of wastes, oxygen, and nutrients between the mother and the fetus.  The fetal blood comes extremely close to the maternal blood in the placenta, but there is no intermingling of fetal and maternal blood.  The fetus and mother can even have, and often do have, different blood types.

Suggested Answer

Oxygen cannot pass through the placenta