Marsupials, such as kangaroos and koala bears, are mammals. Humans are mammals, too. However, there are differences between marsupials and humans. For instance, the average baby human is born after spending 38-40 weeks inside of its mother, but baby marsupials are born after only 4-5 weeks. What feature does a marsupial possess that allows babies to be born earlier? A. an egg sac B. a pouch C. fur D. a uterus