The placenta is usually functioning to deliver nutrients and oxygen to, and remove waste from, the embryonic blood by the __________ of pregnancy.
A) first week
B) second week
C) third week
D) fourth week
E) fifth week
Answer: C
The placenta is usually functioning to deliver nutrients and oxygen to, and remove waste from, the embryonic blood by the __________ of pregnancy.
A) first week
B) second week
C) third week
D) fourth week
E) fifth week
Answer: C