Problem:OPTIONS:
- deserts
- a hydraulic system
- deep valleys
- pyramids
- Calcium carbonate
- patch reefs
- buildings
- Sediment

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

Problem:OPTIONS:
- It decreases
- moves
- contamination
- protect them
- Damages it
- It expands
- Movement
- evaporation

Fact 1: Rain causes erosion. Fact 2: Sediment Exposed soil is susceptible to erosion by wind and rain. Given the two facts above, what does rain do to exposed soil?
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A: Damages it

Problem:OPTIONS:
- With a scale.
- With a ruler.
- With a thermometer.
- With a hydrometer.
- by indirect light
- Under 32 degrees
- focusing a lens
- electron microscope

Fact 1: Aruler is used for measuring the length of an object. Fact 2: Perimeter is the total length around the object. Given the two facts above, how would you measure the perimeter of the outside of an object? ?
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A: With a ruler.

Problem:OPTIONS:
- common traits
- Plant reproduction
- advantageous systems
- undesirable traits
- Animal survival
- competition
- mysterious sytems
- Earth revolving around the sun

Fact 1: Evolution occurs by a process called natural selection. Fact 2: Natural selection only selects functionally advantageous systems. Given the two facts above, what is usually chosen in evolution?
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A:
advantageous systems