This is cyclic change because the population is consistently going up and back down.
 
        
             
        
        
        
When air is heated up the molecules spread out and move faster, so heat rises because it is less dense than the cooler air around it.
        
             
        
        
        
B.
distance from pitcher's mound to home plate = 60 feet; time for baseball to go from pitcher's mound to home plate = 0.4 seconds