Answer:
A
Explanation:
Cardiovascular diseases involves the heart. 
Any of the above options with regards to blood (etc, white blood cells, red blood cells) are related to circulatory system, not affecting the function of the heart. 
Stem cells performing apoptosis to remove old cells is a myth. Stem cells can only differentiate to form cells of the same lineage, not causing other cells to undergo apoptosis. The only external factor that can cause cells to undergo apoptosis is a type lymphocyte in the immune system
 
        
             
        
        
        
The part of the CNS that is responsible for these functions is the brain stem. 
The brain stem is the part of the brain that control very basic functions of your organism and lets them work together as they should. The other parts that are mentioned all have much more specific and also different roles. 
        
                    
             
        
        
        
The first top one is right
        
             
        
        
        
Answer: the beetle is neither harmed nor helped by the mite. 
Explanation:In this case, the mite benefits because it gains transportation from the beetle. If the beetle is neither harmed nor helped by the mite, then the relationship between the mite and the beetle would be an example of commercialism.