Answer:
A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts or human activities such as specicide and human population planning.
Explanation: 
 
        
                    
             
        
        
        
Answer:
B. Black Squirrels have a survival advantage over gray squirrels
Explanation:
Using the information provided, it can be inferred that there is a difference between how many Gray squirrels and how many Black squirrels are being naturally selected. 
This means:
Black squirrels have an advantage that reduces the amount of squirrels being selected from their environment.
Hope this helps!
 
        
                    
             
        
        
        
While scientists have made enormous discoveries, there is always more to learn. Knowledge is built on and reviewed. Sometimes new information reveals an error in understanding from the past. The study of how the world works is always ongoing.
        
             
        
        
        
Answer:
Active transport
Explanation:
To transport the substrate across the membrane it will need energy in the process it's called active transport.
 
        
                    
             
        
        
        
Those things are stored inside your body. Hope this helps! ^-^