What force causes water to run down a mountain
        
             
        
        
        
Answer:
Black holes are merely the most exotic example of the general principle that ... quantum computer stores bits on protons and uses magnetic fields to flip them. ... Powered by Standard Model software, the universe computes 
Explanation:because they are mostly exotic
 
        
             
        
        
        
Answer:
If a substance undergoes a physical change, then it will retain most of its original properties because no new substance is formed.
If a substance undergoes a chemical change, then it will not retain its original properties because a new substance is formed.
Explanation:
So in shorter words its options 2 and 3
 
        
                    
             
        
        
        
No, why? Cause if you're winding up the clock it's basically doing what it needs to do. So there's no need for batteries.. I hope my sad sentence make sense :p
        
             
        
        
        
Answer:
11.7
Explanation:
The pH is the negative logarithm of the concentration of H+ ions. If the concentration is 2×10-¹² the the pH will be -log(2×10-¹²) which is 11.698 which can be round up to 11.7.