Problem:OPTIONS:
- Sediment
- soft soil
- forests
- deep gorges
- cloud cover
- patch reefs
- big oceans
- kalenchoes

Fact 1: Most canyons are formed by flowing rivers through erosion over long periods of time. Fact 2: Deep gorges and canyons formed by the river are tourist attractions. Given the two facts above, what are formed by flowing rivers through erosion over long periods of time?
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A: deep gorges

Problem:OPTIONS:
- Movement of an air mass
- Something that evaporated
- Something that melted
- cloudy and rainy weather
- Something that stayed the same
- Something that froze
- precipitation
- air mass over Earth's surface

Fact 1: Clouds are formed by water vapor rising into colder regions of the atmosphere and condensing. Fact 2: Steam is water vapor produced by evaporation. Given the two facts above, clouds are formed by what going to colder regions?
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A: Something that evaporated

Problem:OPTIONS:
- forces
- volcanoes
- light energy
- allow growth
- thrust
- waves
- mines
- earthquakes

Fact 1: Organisms cluster around hydrothermal vents in the ocean floor. Fact 2: Hydrothermal vents are powered by the heat of submarine volcanoes. Given the two facts above, organisms cluster around formations in the ocean floor powered by the heat of submarine what?
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A: volcanoes

Problem:OPTIONS:
- Something coming from a gland
- A Greek letter
- microorganisms
- polymers of nucleotides
- eggs
- sperm
- white blood cells
- flow of electrons

Fact 1: DNA contains genetic instructions for proteins, and RNA helps assemble the proteins. Fact 2: DNA and RNA RNA and DNA are polymers of nucleotides. Given the two facts above, what help assemble the proteins?
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A:
polymers of nucleotides