By means of natural selection. 
I think natural could be the word 
 
        
             
        
        
        
Answer:
Among some of the numerical abnormalities a karyotype can detect are: Down syndrome (trisomy 21), in which an extra chromosome 21 causes distinctive facial features and intellectual disabilities. Edward syndrome (trisomy 18), in which the extra chromosome 18 translates to a high risk of death before the first birthday.
Explanation:
 
        
             
        
        
        
i believe it would be fat, protein, and carbohydrates but i might be wrong.
 
        
             
        
        
        
Chlorophyll,makes the plant green. large central vacuolestores the water. , cell wall protects the membrane
        
                    
             
        
        
        
Answer:
a
Explanation:
The oceans become larger because of sea-floor spreading.