Which trait characterizes the Class Mammalia status of the white rhino?

Possession of mammary glands for nourishing the young.

The classification of the white rhinoceros into the Class Mammalia is dictated by several distinct physiological adaptations common to all mammals. The most characteristic feature is the presence of mammary glands, specialized structures used by the mother to produce milk to nourish her offspring. Other defining traits include the covering of hair or fur, which aids in insulation, and being endothermic, meaning they generate internal heat to maintain a stable, warm body temperature regardless of the environment. Furthermore, the white rhino is specified as a placental mammal, indicating that the embryo develops internally within the mother's uterus, sustained through nourishment provided by a placenta.