Problem:OPTIONS:
- making trees
- staying warm
- engines
- replanting trees
- cooking food
- removing heat
- Electrical energy
- warmth

Fact 1: Burning wood is used to produce heat. Fact 2: Food is cooked by the steam and heat. Given the two facts above, what is burning wood used for?
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A: cooking food

Problem:OPTIONS:
- high temperature
- movements in the earth's crust
- human migration
- exposure to cold
- cloud formation
- energy of moving objects
- soil
- degrees Celsius

Fact 1: An earthquake causes the ground to shake. Fact 2: Earthquakes are movements in the Earth's crust. Given the two facts above, what causes the ground to shake?
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A: movements in the earth's crust

Problem:OPTIONS:
- Animal survival
- define boundaries
- poison predators
- competition
- competing for resources
- detract enimines
- animal transport
- camouflage sent

Fact 1: Male dogs use pheromones in urine to mark their territory. Fact 2: For a male, urine markings are used to define the boundaries of their territory. Given the two facts above, what do the pheromones in male dog urine used for?
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A: define boundaries

Problem:OPTIONS:
- decomposition and respiration
- storing water
- photosynthesis and solar energy
- near the shoreline
- precipitation and run-off
- perspiration and excretion
- The area was once underwater
- At the peak of a mountain

Fact 1: Lakes are formed by precipitation and runoff. Fact 2: Runoff from precipitation is a natural part of the water cycle. Given the two facts above, what are some of the steps that forms a lake?
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A:
precipitation and run-off