Niagara Falls Were Formed ________

question 85

Multiple Choice

Niagara Falls were formed ________.

• A) by humans as a result of the damming of the St. Lawrence River
• B) during Precambrian time approximately a billion years ago
• C) so long ago that the river's knickpoint is now gone
• D) after the retreat of the Pleistocene ice sheets a few thousand years ago
• E) after a series of spectacular earthquakes which are still helping the falls evolve

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