Steamboats. Steamboats positively effected the world because they made the transportation of goods more efficient and economical. Travel time was cut in half and were a compliment of the railroads, both for commercial and passenger transportation. Steamboats were independent on the wind speed and direction.
        
             
        
        
        
I believe the answer is: <span>a secret intelligence "finding" signed by the president
Even if there is no fact about the finding, all of them had legal ground to act on their own since the finding is acknowledge by the president.
The signed finding indicates that even if their actions were a mistake, the the president would take the responsibility for their action.</span>
        
             
        
        
        
The answer would be B.) Brown Vs. Board of education because The United States Supreme Court declared state laws establishing separate public schools for black and white students to be unconstitutional.