Answer:
my guess is C
Explanation:
All you have to do is eliminate the ones that don't make sense and c is the only one left
 
        
             
        
        
        
Genetic traits that survive through selection increase throughout a population.
 
        
             
        
        
        
Answer:
Blood Brain Barrier(BBB)
Explanation:
This is a biological interface of special endothelial cells of astrocytes, pericytes , capillaries,  neurons and other  structures, acting as a physical barrier or  gate separating the Central Nervous system from the peripheral  blood circulations. Thus it  formed a tight junction serving as a  physical barrier to  selectively regulate the entrance of substances from the   cerebral blood flow   into the brain,  therefore maintaining homeostasis of the brain.
From above any  substances  absorbed into the blood stream  irrespective of the mode of entry  are transported through  the BBB, and  are selectively  regulated to enter the brain cells by the BBB's   interactions with the blood vessels, hormones etc. 
Basically it allows the passage of nutrients,  a few  drug, hormones and resists certain toxins and pathogens for the brain homeostasis.
 
        
             
        
        
        
As a rule of thumb, a person will eliminate one average drink or . 5 oz (15 ml) of alcohol per hour. Several factors influence this rate. The rate of elimination tends to be higher when the blood alcohol concentration in the body is very high.
        
             
        
        
        
For the answer to the question above, I will just complete the missing word for your statement. 
<span>Regions of the CNS with an abundance of myelinated axons constitute the "White" matter. </span>
The answer is "white"
I hope my answer helped.