Kaplan Nursing Entrance Practice Exam

Which group of mammals gives birth after a short time and further develops their young in an external pouch?

1. Reptiles

2. Placental mammals

3. Marsupial mammals

4. Monotremes

The correct answer is: Marsupial mammals

The group of mammals that gives birth after a short gestation period and further develops their young in an external pouch is marsupial mammals. Marsupials, such as kangaroos and koalas, have a unique reproductive strategy where the young, often referred to as joeys, are born at a very undeveloped stage. After birth, the tiny joey crawls into the mother's pouch, where it attaches to a teat and continues to grow and develop. This pouch provides a secure environment, allowing the young to gain nutrition and protection until they are fully developed enough to leave the pouch and begin a more independent life. In contrast, reptiles do not give live birth and often lay eggs, while placental mammals generally have a longer gestation period, during which the fetus develops internally before being born. Monotremes, another group of mammals, lay eggs rather than giving live birth, which distinguishes them from marsupials. Thus, the distinct reproductive characteristic of marsupials is what makes them the correct answer.