x or y because both can cause it 
 
        
             
        
        
        
I believe it's A, but I could be wrong. I apologize if I am so. I will do further research and get back to you
        
                    
             
        
        
        
Chemically speaking, enzymes are composed of chains of amino acids, and they are considered to be a type of protein.
        
             
        
        
        
Through the process of transformation. Hope this helps.
        
             
        
        
        
Answer:
Gravity
Explanation:
Percolation is the process of a liquid slowly passing through a filter. It's how coffee is usually made. Percolation comes from the Latin word percolare, which means "to strain through." Percolation happens when liquid is strained through a filter, like when someone makes coffee.
Evaporation-the process of turning from liquid into vapor.
Condensation-water which collects as droplets on a cold surface when humid air is in contact with it. 
and gravity- Gravity is the force of attraction between two objects, and Earth's gravity pulls matter downward, toward its center. It pulls precipitation down from clouds and pulls water downhill. The warm water near the surface of the ocean heats up with sunlight and evaporates, keeping the water cycle in motion.