Hello!
The answer you were looking for is....
(D) Nonpoint source pollution is difficult to regulate, because its source is difficult to track.
 
        
             
        
        
        
Answer: B
Explanation: the sun is made of gas, which doesn't all spin together at the same speed like a solid rock would.
 
        
             
        
        
        
To test for side effects and rare effects (the bigger the sample size, the more likely that wired things may occur)