Which group comprises mammals that have a placenta enabling nutrient and gas exchange between mother and embryo?

Which group comprises mammals that have a placenta enabling nutrient and gas exchange between mother and embryo?

• A. Primates
• B. Marsupials
• C. Monotremes & Examples
• D. Placental mammals

Answer: (D)

The key idea is how the embryo gets nutrients and oxygen while developing inside the mother. In placental mammals, a true placenta forms between the embryo and the mother, linking their blood supplies and enabling efficient exchange of nutrients and gases throughout a lengthy gestation. This supports longer, in-utero development. Monotremes lay eggs and do not form a placenta. Marsupials have a much simpler placental connection and give birth to relatively undeveloped young that complete their development after birth (mostly via lactation). Humans, whales, mice, and other placental mammals all share this characteristic. So, the group with this fully functional placental connection is the placental mammals.

The key idea is how the embryo gets nutrients and oxygen while developing inside the mother. In placental mammals, a true placenta forms between the embryo and the mother, linking their blood supplies and enabling efficient exchange of nutrients and gases throughout a lengthy gestation. This supports longer, in-utero development.

Monotremes lay eggs and do not form a placenta. Marsupials have a much simpler placental connection and give birth to relatively undeveloped young that complete their development after birth (mostly via lactation). Humans, whales, mice, and other placental mammals all share this characteristic.

So, the group with this fully functional placental connection is the placental mammals.