Answer:
It's in their makeup to interact
Explanation
They need to interact to survive, to exist, to reproduce!
 
        
                    
             
        
        
        
Answer:
A.The two proteins have different functions.
Explanation:
 
        
             
        
        
        
An under water volcano is called a submarine valcano
        
                    
             
        
        
        
Answer:
C
Explanation:
The brother has different alleles for the blood type gene than his sister does.  Blood type is inherited from parents like many other traits that can be displayed on a punnet square.  Depending on what the parents blood type alleles were, the brother and sister could have different blood types.  
A different number of chromosomes doesn't lead to different blood types, so D is wrong.  And A is incorrect because the number genes also does not affect blood type.  And I think the blood type genes are on the same chromosome, so B is wrong.  C is correct because blood type is inherited by alleles, and different alleles can cause different traits, such as blood types.