Blood types:
AB +
AB -
A +
A -
B +
B -
O +
O -
It is possible to have a child with O blood despite the parents having different blood types.
While the man tested for B blood, he could have been a combination between type o and B whereas, the woman was a combination of type A and o. Since A/B are dominant, they would 'stand out' contrarily to o. 
This means that their children could have AB or O blood. 
 
        
                    
             
        
        
        
D: All the variables are controlled except one.
        
                    
             
        
        
        
<span>Pets might have fleas and other diseases that could be transferred to the food either by the pet directly coming into contact with the food or by way of employees after they come in contact with the pet. This is especially dangerous if the food establishment does not have very strict sanitation rules.</span>
        
             
        
        
        
Answer:
hope you like it
Explanation:
A molecular clock determines evolutionary relatedness by examining how many mutations or random changes in DNA, there are between two organisms. When we map the relatedness of different organisms, we are creating a phylogenetic tree. At some point, all organisms that are alive today shared a common ancestor.
 
        
                    
             
        
        
        
Answer:
I am positive the answer is C because I used to study the exact same lesson.