Becuase you will get the species mixed up 
        
             
        
        
        
Answer:
Possession of inherited adaptations that maximize fitness. 
Explanation:
Basically ones that are best adapted for their environment. (I'm assuming "he" is Darwin?)
 
        
             
        
        
        
When the heterozygous phenotype<span> is </span>intermediate between the two homozygous phenotypes<span>, the pattern of inheritance is called incomplete dominance. Multiple Alleles. Although an individual can </span>have<span>at most </span>two<span> different alleles, a species may </span>have<span> multiple alleles of many of its genes.</span>
        
             
        
        
        
Acetylcholine (ACh)
Acetylcholine is an organic chemical that functions in the brain and body of many types of animals as a neurotransmitter.