B it's a vegstigial trait
Many biology texts today still refer to the appendix as a vestigial organ
        
                    
             
        
        
        
In an experiment, that subjected participants to increasing isolation in a computerized ball-tossing game, fMRI scans showed activity in the cingulate cortex, a region of the brain that is active during EMOTIONAL PAIN. 
Cingulate cortex is the limbic lobe involved in emotion formation, memory, learning, problem solving and self control.  
        
             
        
        
        
<span>Traits are determined by proteins that are built according to the instructions stored in the genes.</span>
        
             
        
        
        
If they are trying to convert any measurements or just measure out the chemicals, it wouldn't be very familiar to them so they could make a mistake that can result of too much or too little of the chemicals, which can make the chemicals react differently. 
        
             
        
        
        
 <span>A flashlight is to battery as your body is to: FOOD.</span>