Humans adapt to changes in the environment by genetic change, developmental adjustments, acclimatization, and cultural or technological advances.  
 
        
             
        
        
        
was a period of rapid colonization of the African continent by European powers. But it wouldn't have happened except for the particular economic, social, and military evolution Europe was going through.
 
        
                    
             
        
        
        
A line segment on a graph would be any line that isn't continuous. It would have dots on the ends instead of arrows. Is that what you're asking?
        
             
        
        
        
The war in Syria start on March 15, 2011.
hope that helps