The correct answer would be A. The number of neutrons present in Krypton-82 would be 46. The atomic number of an atom represents the number of protons present while the mass number is the sum of the neutrons and protons in the atom. The mass number for the given atom is 82. So, 82-36 = 46 neutrons present.
        
                    
             
        
        
        
The law of conservation of mass states that the mass will stay constant given a chemical reaction because no atoms were created or destroyed. This being said, an example can include water evaporating in a clear bottle outside on a hot day ( the mass of the bottle will stay the same, but the liquid water evaporated into gaseous water).
        
             
        
        
        
Hi,
The answer would be day.
I hope this helps!
        
                    
             
        
        
        
An ancient medicinal plant
        
             
        
        
        
Based on the description, I believe your answer would be 
B.) The sun heats the Earth's atmosphere
Hope this helps!<span />