Q: An axe head and a doorstop are types of what simple machine? Choices: - pulley - blade - lever - wedge A:
wedge
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Q: Which gases trap heat in the atmosphere? Choices: - fluorine and nitrogen - methane and helium - ozone - greenhouse A:
greenhouse
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Q: When does internal reflection occur? Choices: - when light goes from a slow medium to another slow medium - when light goes from a fast medium to a slow - when light goes from a fast medium to another fast medium - when light goes from a slow medium to a fast A:
when light goes from a slow medium to a fast
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Q: Life probably began where? Choices: - rocks - the Sun - caves - oceans A:
oceans
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