N An effect of third-party candidates, such as Theodore Roosevelt, on presidential elections is
O they usually win the popular vote
• they often help Republicans.
O they often help Democrats.
they change oycomes of elections.

D.

Explanation:

Third-party, also known as minor party, is one of the political party in the United States. The third-party stands in oppose with other two major political party of the United States, that is, the Republicans and the Democrats.

The effect that a third-party candidates can have on presidential election is that they can change the outcome of the elections. Considering the example of Presidential election of 1912, when President Theodore Roosevelt opted to go for presidential elections and formed his own party named 'the  Bull Moose Party.' This third-party candidancy changed the outcome of the elections.

Therefore, correct answer is option D.

in 1897, pershing became a tactical officer at west point, and that's where he was given the nickname "black jack." pershing's first name is "john," for which "jack" is a nickname, and he was a white man who commanded black troops. hence "black jack".