Answer:
Long beaks of medium ground finches allows them to opt for alternate sources of food in times of extremities while this is not the case with the cactus finches. 
Explanation:
The medium ground finches have larger beaks and thus apart from small seeds they can also break open the large seed. In case if the small seeds get scarce, a medium ground finch can still survive by taking advantage of feeding on alternate source of food but small beaked birds such as cactus finches shall die out of starvation. 
This adaptation of medium ground finches gives it a survival advantage over the cactus finches
 
        
                    
             
        
        
        
Yes, the planet obeys the Kepler's Second Law. It is because it moves at equal time of one month at the same distance.
        
             
        
        
        
An adaptation-----------------------