As the height increases the temperature decreases.it gets very cold, very windy, and low in all atmosphere gases, including oxygen. The top of Everest in the "kill zone" is expressed to all which is above 8,000 meters. Its caused by the low air pressure which causes fluid to leak into the lungs and results in drowning you. Also low oxygen causes mental dysfunction. You cannot think straight and get confused and will make bad decisions Overall its not good above 8,000 meters.
why?planing to climb the Everest?