D 
Because in the nervous system messages travel faster
        
                    
             
        
        
        
Botanist
Biologist/Biological Scientist: A scientist who studies living organisms and living systems. Botanist: A scientist who studies plants. Chemical Ecologist: A scientist who studies chemicals in the interactions of living organisms. Chief Scientist: A scientist who leads other scientists in a particular research area.
        
                    
             
        
        
        
I am pretty sure it is glycogenesis<span>. Please tell me if I'm wrong.</span>
        
             
        
        
        
Answer:
Different brands of nail polishes used by Sarah.
Explanation:
While conducting an experiment two different variables are considered namely dependant variable and independent variable. The variable which is continuously changed to see the effects is called as independent variable and the variable which is being tested is called as dependant variable. 
In the given scenario, Sarah want to know best brand of nail polishes which lasts longest without chipping. Thus the different brands of nail polish used by her is considered as independent variable.
 
        
             
        
        
        
The intermediate disturbance hypothesis predicts that species diversity will be  highest  when the frequency and/or intensity of disturbances are intermediate
Explanation:
The diversity of the species is maximised at an intermediate near of anthropogenic as well as natural disturbances. As the competitively inferior disturbances are being tolerated for species disturbance and are termed to be dominant. Co exist of the sensitive species when the disturbance are either frequent or rare, which possess the reduced level of the disturbances. the productivity is predicted as very less due to competitive exclusion. As the disturbances increases productivity becomes less as most of them unable to sustain the regular destructive occurrence. So with the intermediate disturbances productivity is high as the rapid colonizers and dominant competitors are able to coexist.