The overall structure is said to be a double helix composed of nitrogenous bases and the sugar backbone. It is also double stranded too
        
             
        
        
        
Answer: Option A
Explanation:
When Andrew was exposed to the virus causing chicken pox he got infected and the virus crossed the blood brain barrier.
During the early stages when Andrew was a child there will be as such no effect of the virus in the brain. 
During the early stage the virus will remain in the brain and cause harm in the later days when Andrew will be older.The virus can alter the brain functions such as homeostasis, blood brain barrier functions.It enters the brain while damaging the nervous system.
 
        
             
        
        
        
Yes I think you are right. It does not contain setae for food to travel to the anus. But it's something else that develops the food into poop and travels through anus
Hope this helps :)
        
             
        
        
        
The answer is the last one. Countercurrent multiplication in the kidneys is the way toward utilizing vitality to create an osmotic slope that empowers you to reabsorb water from the tubular liquid and deliver concentrated pee. It is discovered broadly in nature and particularly in mammalian organs. 
Countercurrent multiplication was initially considered as a system whereby pee is gathered in the nephron. At first, concentrated in the 1950s by Gottschalk and Mylle following Werner Kuhn's hypotheses, this instrument picked up notoriety simply after a progression of confounded micropuncture tests.
        
                    
             
        
        
        
As a cell grows, its volume increases more than its surface area  so the answer is C