Answer:
melanin affects how one looks (1st question)
cause and effect (2nd question)
Explanation:
for the 2nd question, its cause and effect because uv rays hit our skin and our skin is affected which gives us suntan.
 
        
                    
             
        
        
        
Answer: genetic variation
 
        
             
        
        
        
Answer:
the light brown mouse 
Explanation:
because then they would be able to blend in with the sand 
 
        
             
        
        
        
That is when extinction occurs. Hope I helped!