MICROANATOMY

Detailed explanation-1: -Placental mammals all bear live young, which are nourished before birth in the mother’s uterus through a specialized embryonic organ attached to the uterus wall, the placenta.

Detailed explanation-2: -Placental mammals are therian mammals in which a placenta develops during pregnancy. The placenta sustains the fetus while it grows inside the mother’s uterus. Placental mammals give birth to relatively large and mature infants. Most mammals are placental mammals.

Detailed explanation-3: -The eutherian or ‘placental’ mammals, like humans, make up the vast majority of today’s mammalian diversity. Eutherians all have a chorioallantoic placenta, a remarkable organ that forms after conception at the site where the embryo makes contact with the lining of the mother’s uterus (Langer, 2008).