Mammals whose immature offspring complete their development in an external pouch are known as

Mammals whose immature offspring complete their development in an external pouch are known as

• A. Monotremes
• B. Placental mammals
• C. Eutherians
• D. Marsupials

Answer: (D)

Mammals whose immature offspring complete their development in an external pouch are marsupials. After a brief, early gestation, the newborn is highly underdeveloped and crawls into the mother's pouch, where it attachs to a teat and continues growing in a protected environment. This pouch-based development is a defining feature of marsupials such as kangaroos, koalas, and opossums. In contrast, monotremes lay eggs and their young hatch outside the body; placental mammals (eutherians) develop inside the uterus with a placenta and give birth to relatively more mature young. So, the best fit for this developmental pattern is marsupials.

Mammals whose immature offspring complete their development in an external pouch are marsupials. After a brief, early gestation, the newborn is highly underdeveloped and crawls into the mother's pouch, where it attachs to a teat and continues growing in a protected environment. This pouch-based development is a defining feature of marsupials such as kangaroos, koalas, and opossums. In contrast, monotremes lay eggs and their young hatch outside the body; placental mammals (eutherians) develop inside the uterus with a placenta and give birth to relatively more mature young. So, the best fit for this developmental pattern is marsupials.