The answer is: [A]: troposphere .
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Hello There! ^_^
Your question: What were the three main Indian groups before European explorers arrived..?
Your answer: The Mayan, the Aztecs and the Incas were the three main Indian groups before European explorers arrived.
Hope this helps!
The answer is a hope this is helpful
C. Ultraviolet light shining on the minerals will cause them to give off visible light.