iF YOU KNOW ABOUT KANGAROOS! ANSWER!! HELLPP!!?

Question

How long does the baby kangaroo spend inside its mother's pouch?

Which are more likely to survive placental babies or marsupial babies?

Did the mammals in the northern continents generally evolve into placentals or marsupials?

Did the mammals in Austraila generally evolve into placentals or marsupials?

Answer 1

1. Immediately after birth it crawls up the mother's body and enters the pouch. The baby attaches its mouth to one of four teats, which then enlarges to hold the young animal in place. After several weeks, it becomes more active and gradually spends more and more time outside the pouch, which it leaves completely between 7 and 10 months of age.

2. The early birth of marsupials removes the developing young much sooner than in placental mammals, and marsupials have not needed to develop a complex placenta to protect the young from its mother's immune system. Early birth places the tiny new-born marsupial at greater risk, but significantly reduces the risks associated with pregnancy, as there is no need to carry a large fetus to full-term in bad seasons. In most continents, placentals were much more successful then marsupials.

3. Most modern mammals--including ourselves--are placentals, in which the developing young are nurtured inside the uterus. They are believed to have originated in the northern hemisphere more than 100 million years ago and then slowly spread throughout the globe.

4. Fossil record shows that marsupials and placental mammals coexisted in Australia, however, only marsupials have survived to the present. The placental mammals made their reappearance in Australia and bats and rodents started to appear.