Answer: D relative humidity
Explanation: Just took the test.
 
        
             
        
        
        
• Before the balloon was placed inside the hot water, the pressure was the same inside and outside the balloon. The hot water raised the kinetic energy of the air molecules inside the balloon, expanding the balloon, through thermal expansion.
• (1) the pressure of air inside the balloon increased, (2) the volume of the inside of the balloon increased as well, and (3) the temperature of the balloon increased. Note that pressure and volume are inversely proportional, and pressure and temperature are directly proportional. Therefore as the temperature increases, the pressure inside will increase, causing an increase in the volume. At a certain point though the volume will increase too much as to cause a significant decrease in pressure.
• The air molecules will gain kinetic energy, hence (1) increasing the molecules's speed, and (2) heating the air molecules.
 
        
             
        
        
        
Explanation:
put them in where the letters start with
 
        
             
        
        
        
Explanation:
Relation between pH and concentration of hydrogen ions is as follows.
                   pH = ![-log [H^{+}]](https://tex.z-dn.net/?f=-log%20%5BH%5E%7B%2B%7D%5D)
So, it means that an increase in the value of pH will show that there occurs a decrease in concentration of hydrogen ions.
Therefore, the solution becomes basic in nature.
On the other hand, a decrease in the value of pH will show that there occurs an increase in the concentration of hydrogen ions.
Therefore, the solution becomes more acidic in nature.
Hence, if the pH of a solution is decreased from pH 8 to pH 6 it means that the concentration of hydrogen ions has increased in the solution.
 
        
                    
             
        
        
        
I would say the answer is C
hope this helps :)