The answer to your question is option b 
This is because if the trees are black, and covered with soot due to the pollution, caused by industrialisation, the white moths will be easily seen and constantly hunted by the predator, compared with the black moth population as they camouflage easily. Ultimately, the white moths would be hunted to such an extent that their population would dramatically decrease
        
             
        
        
        
Explanation:
B has water as a reactant
 
        
             
        
        
        
<span>because meristems can differentiate in each tissue system of a plant, a cutting that contains meristems that can form a new plant.</span>