The nurse is reviewing fetal and maternal circulation with a group of nursing students. Which statement by a student demonstrates a need for further clarification?

"The placenta is the site of gas exchange for the fetus."

"The umbilical arteries carry deoxygenated blood from the fetus to the placenta."

"The fetal heart pumps blood to both the placenta and the developing organs."

"Maternal and fetal blood mix to allow for nutrient and oxygen exchange."