C. the execution of the last Inca ruler, Atahualpa
        
                    
             
        
        
        
They allowed for travel against a rivers current Hope this helps! ;D
        
                    
             
        
        
        

A war is only just if it is fought for a reason that is justified, and that carries sufficient moral weight. The country that wishes to use military force must demonstrate that there is a just cause to do so. ... Sometimes a war fought to prevent a wrong from happening may be considered a just war.
 
        
                    
             
        
        
        
The correct answer should be c. education
Education has always been a big thing even in the times of the colonies. The US had the first university much before many countries worldwide even had high-schools.