Well he made the natives slaves. He . His men raped the native American women. 
 
        
             
        
        
        
Answer:
It was Theodore Roosevelt
Explanation:
The president during the construction of the Panama Canal was Theodore Roosevelt
 
        
                    
             
        
        
        
Answer: Here's a reason.
Explanation:
The release of two atomic bombs on Japan in August 1945 helped end World War II but ushered in the Cold War, a conflict between the United States and the Soviet Union that dragged on nearly half a century. In the United States, the use of the bombs was widely praised by a public tired of war and high casualties.
Hope I helped.
 
        
             
        
        
        
Chemical change.
It would be a chemical change or reaction because the substance is changing its chemical makeup.