MICROANATOMY

Detailed explanation-1: -And humans, of course, are also placental mammals . 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: -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).

Detailed explanation-3: -There are now thought to be three major subdivisions or lineages of placental mammals: Boreoeutheria, Xenarthra, and Afrotheria, all of which diverged from common ancestors.

Detailed explanation-4: -Four major superordinal placental (i.e., eutherian) mammalian clades are supported by molecular data (9, 13). These clades are the Afrotheria, Xenartha, Euarchontaglires, and Laurasiatheria.