I believe that the answer is B
        
                    
             
        
        
        
The answer to the question presented above would be letter b. amount of dissolved gases. The increased pressure increases the body's amount of dissolved gases. This change to air pressure greatly affects the human body and these changes can happen when going into the depths of the ocean or when climbing mountain peaks. 
        
                    
             
        
        
        
The 3 great empires were the Mughal, Ottoman, and the Safavid empire.
        
             
        
        
        
Answer: King of the Franks, then King of the Lombards, then Emperor of the Romans. 
During the early middle ages, he united the majority of the western and central Europe. He founded the Holy Roman Empire. 
Explanation: