Problem:OPTIONS:
- humans disturb it
- frontal zones
- in lakes
- at the ocean
- our planet
- at the poles
- mouth of rivers
- at the equator

Fact 1: Biodiversity generally increases from the poles to the equator. Fact 2: Biodiversity contributes to ecosystem complexity. Given the two facts above, where is ecosystem complexitiy generally least?
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A: at the poles

Problem:OPTIONS:
- to use resources
- organisms produce offspring.
- sub-units of species
- things don't die
- the Earth being tilted
- production of energy
- to keep going
- by keeping them warm

Fact 1: Reproduction is the process by which organisms give rise to offspring. Fact 2: Life continues because of reproduction. Given the two facts above, why does life continue?
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A: organisms produce offspring.

Problem:OPTIONS:
- exposure to cold
- Something that causes allergies
- air
- electricity causing death
- a tree falling
- water
- Electrical energy
- food

Fact 1: Electrocution causes harm to an organism. Fact 2: Electrical exposure causing death is referred to as electrocution. Given the two facts above, what causes harm to an organism?
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A: electricity causing death

Problem:OPTIONS:
- Sediment
- Fresh water
- loose soil
- swamp vegetation
- mussels
- storing water
- body water
- carbon dioxide

Fact 1: Damming a river can cause a lake to form. Fact 2: Water in the lakes is fresh, cool and transparent. Given the two facts above, what is the thing that is created by damming a river made of?
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A:
Fresh water