The developments that did the most to end the middle ages were the

executive, (president and about 5,000,000 workers) legislative (senate and house of representatives) and judicial (supreme court and lower courts)

explanation:

no statements but ok.

the statement that best describes the idea of manifest destiny that was used in the 19th century would be that "it was fate that the united states would continue to  expand westward," since people thought the us was "destined" to do so.