Natrual variations i think 
        
                    
             
        
        
        
Answer:
Explanation:
What is Ozone? Ozone is a gas made up of three oxygen atoms (O3). It occurs naturally in small (trace) amounts in the upper atmosphere (the stratosphere). Ozone protects life on Earth from the Sun's ultraviolet (UV) radiation.
 
        
             
        
        
        
Answer:
toward the 20% solute side of the membrane
Explanation:
that is the process of osmosis, in which the water moves in the direction that tends to equalize the solute concentrations on the two sides. 
Basically it's to make it 50% 50%, so the water moves to the 20% solute side to raise the %
I hope it's clear enough.