Explanation:
In mammalian embryos, waste products such as carbon dioxide and urea are transferred from the fetus to the mother through the placenta. This organ facilitates the exchange of nutrients, gases, and waste between the maternal and fetal bloodstreams.
Why not the other options?
(A) Ureter: This is a duct that carries urine from the kidneys to the bladder in adult mammals, not directly involved in fetal waste elimination.
(B) Allantois: An extra-embryonic membrane involved in early fluid exchange and waste storage; in mammals, it contributes to forming the umbilical cord but does not directly eliminate waste.
(D) Amniotic fluid: This fluid surrounds and protects the fetus but is not involved in waste elimination.
Therefore, the placenta is the primary structure responsible for eliminating excretory products of the mammalian embryo.
Explanation by: Official MCQ Buddy
In mammalian embryos, waste products such as carbon dioxide and urea are transferred from the fetus to the mother through the placenta. This organ facilitates the exchange of nutrients, gases, and waste between the maternal and fetal bloodstreams.
Why not the other options?
(A) Ureter: This is a duct that carries urine from the kidneys to the bladder in adult mammals, not directly involved in fetal waste elimination.
(B) Allantois: An extra-embryonic membrane involved in early fluid exchange and waste storage; in mammals, it contributes to forming the umbilical cord but does not directly eliminate waste.
(D) Amniotic fluid: This fluid surrounds and protects the fetus but is not involved in waste elimination.
Therefore, the placenta is the primary structure responsible for eliminating excretory products of the mammalian embryo.