1) Warm-bloodedness, 4-chamber heart,
2) the appearance of alveolar lungs,
3) the development of the cerebral cortex (which ensured the wide adaptation of mammals to environmental conditions. This led to a complication of behavior, the rapid formation of conditioned reflexes);
4) feeding the young with milk,
5) the appearance of multilayer skin rich in glands.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.