Q: An axe head and a doorstop are types of what simple machine? Read this paragraph and choose the correct option from the provided answers: The axe head and the doorstop are both examples of a wedge, a type of simple machine. Choices: - pulley - blade - lever - wedge A:
wedge
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Q: Which gases trap heat in the atmosphere? Read this paragraph and choose the correct option from the provided answers: Greenhouse gases trap heat in the atmosphere. These gases include carbon dioxide, methane, water vapor, and ozone. Choices: - fluorine and nitrogen - methane and helium - ozone - greenhouse A:
greenhouse
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Q: When does internal reflection occur? Read this paragraph and choose the correct option from the provided answers: Total internal reflection occurs when light goes from a slow (high index of refraction) medium to a fast (low index of refraction) medium. With total internal reflection, light refracts so much it actually refracts back into the first medium. This is how fiber optic cables work: no light leaves the wire. 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? Read this paragraph and choose the correct option from the provided answers: Life probably began in the oceans. No one knows exactly how or when. Life may have originated more than once. If life began before the Moon formed, that impact would have wiped it out. Then life would have had to originate again. Eventually conditions on Earth became less violent. The planet could support life. Choices: - rocks - the Sun - caves - oceans A:
oceans
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