Humans hear frequencies from 20 Hz<span> (low) up to </span>20,000 Hz (high)
 
        
        
        
Not sure but i will say D
 
        
                    
             
        
        
        
Answer:
B.
Explanation:
According to CDC, if you’re doing moderate-intensity activity, you can talk but not sing during the activity.
 
        
                    
             
        
        
        
Scott needs to determine the density of a metallic rod. First, he should determine the mass of his sample on the laboratory balance. Second, he should measure the volume of his sample by water displacement. Finally, he can calculate the density by dividing mass/volume. 
Hope this helped ;)
        
             
        
        
        
To what i see, the answer is....
C.