Answer: Because it is harder to draw breath in. And the cold
Explanation: At higher altitudes, it becomes more dangerous, and you can develop altitude-related illnesses such as HAPE and HACE. I read a book called<em> Into Thin Air</em>, and in the book the author goes into detail on the details/complications of climbing Mt.Everest and oxygen needs. Mountain climbers use canisters of oxygen called <u>Supplemental Oxygen.</u>
 
        
             
        
        
        
Answer:
El jabón líquido se obtiene frecuentemente de la saponificación de aceites o grasas con un alto contenido de ácido oleico y una mezcla proporcional de hidróxido de sodio y de potasio. El resultado es un producto de color oscuro y olor fuerte
 
        
             
        
        
        
Gravitational attraction between two celestial objects (i think)
        
             
        
        
        
Answer:
Oxygen debt is a physiological phenomenon in which a person consume oxygen at fater rate that it replaced by new oxygen molecules.
As shown in the graph, oxygen debt occurs just after the end of exercise because oxygen is consumed at faster rate during exercise that leads to  increased respiration and body attempts to replace the used oxygen.
To overcome the problem of oxygen debt, a person should take rest that allows the body to replenish its oxygen supply.
 
        
             
        
        
        
Answer:
Coagulation begins almost instantly after an injury to the endothelium lining a blood vessel. Exposure of blood to the subendothelial space initiates two processes: changes in platelets, and the exposure of subendothelial tissue factor to plasma factor VII, which ultimately leads to cross-linked fibrin formation.
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<u><em>Hope this helps :)</em></u>
<u><em>Pls brainliest...</em></u>