He should raise his hand and wait for a teacher
        
                    
             
        
        
        
It is choice B.
Haploid cells contain one copy of genetic information. (ex sperm, egg)
Diploid cells contain two copies of the genetic information. (ex muscle,  bone brain, eye, etc.)  
        
             
        
        
        
Answer:
sinoatrial node and atrioventricular node
 
        
             
        
        
        
You multiply the magnification of the lenses (usually x10) by the magnification of the setting