The historian Frederick Jackson Turner argued that the frontier shaped America by?:

A. killing off many of the most adventurous individuals.

B. stimulating individualism, nationalism, and democracy.

C. producing institutions very much like those of Europe.

D. creating new opportunities for women.

The correct answer is letter B. stimulating individualism, nationalism, and democracy. The historian Frederick Jackson Turner argued that the frontier shaped America by stimulating individualism, nationalism, and democracy. Frontier Thesis is the conclusion put forth by Frederick Jackson Turner that the origin of American exceptionalism created freedom, constantly named as civilization, etc.