Explanation:
For question no 19
Force (F) = 20N
distance (d) = 5m
Work = F * d
 = 20 * 5
 = 100 J
Now
For question no 20
D. No matter how much force is applied the object must have motion for work to be done. 
 
        
                    
             
        
        
        
Answer:
D because asexual reproduction allows an organism to make a baby anytime, and so you dont need a male and female thus making it easier to make a baby
Explanation:
 
        
             
        
        
        
At room temperature and normal atmospheric pressure, covalent compounds may exist as a solid, a liquid, or a gas, whereas ionic compounds exist only as solids, Ionic compounds exist in stable crystalline structures. Therefore, they have higher melting and boiling points compared to covalent compounds.
 
        
             
        
        
        
Its An experiment because it doesnt ask a testable question
So its B
i hoped it helped SIS