Question:
Use evidence from the fact that contact between rocks over long periods of time causes rocks to smooth to answer the following question. OPTIONS:
- where thunder was heard
- where water has flowed for years
- where wind has blown for days
- where the human population is the highest "Where would rocks be the smoothest?"

Answer:
where water has flowed for years

Question:
Use evidence from the fact that the circulatory system brings oxygen from the lungs to the rest of the body to answer the following question. OPTIONS:
- is poisonous to humans
- is used to make balloons rise into the air
- humans exhale as well
- our circulatory system spreads to our body from our lungs "Plants expel a gas that"

Answer:
our circulatory system spreads to our body from our lungs

Question:
Use evidence from the fact that a car engine is a source of heat to answer the following question. OPTIONS:
- rubbing noses
- swimming in Antartica
- touching ice
- sitting in freezers "A source of heat might be"

Answer:
rubbing noses