How does human evolution or natural selection relate to the susceptibility of disease

Human evolution, and natural selection are processes during which humans/living beings get accustomed to their surroundings, improve, and fight for survival, because if they don't, they will die. Diseases have always been present during the evolution and natural selection processes, as a way of determining who is fit enough to survive, and who will succumb to those diseases and disappear. 

The need activity of the nurse is to suction discharges from the trachea. current treatment approaches in the pressing consideration facilities or crisis offices are corticosteroids and nebulized epinephrine; steroids have demonstrated advantageous in extreme, direct, and even gentle croup. in the clear instances of croup, anti-microbials are not endorsed, as the etiology is viral