Fact 1: Lung cancer is most often caused by exposure to tobacco smoke. Fact 2: Tobacco is smoked in pipes or in cigarettes or bidis. Given the two facts above, what is lung cancer most often caused by?
OPTIONS:
- the Moon
- Pollution
- sunlight
- Chemical energy
- fossil fuels
- cigarettes
- burning
- marijuana smoke

Answer: cigarettes

Fact 1: Powering an electrical device with a battery requires a path for electricity to flow through a closed circuit. Fact 2: An electrical current is a flow of electrons. Given the two facts above, powering a device with a battery requires a path for electrons to flow through ?
OPTIONS:
- electromagnetic energy
- direct energy
- rays or beams
- hydrogen and oxygen
- heat energy
- a closed circuit
- kinetic energy
- an object

Answer: a closed circuit

Fact 1: Coal is used for generating heat by burning. Fact 2: Like coal, petroleum is a fossil fuel. Given the two facts above, what is used for generating heat by burning?
OPTIONS:
- Calcium carbonate
- carbon dioxide
- fossil fuels
- clouds
- peachleaf willow
- space
- calcite
- sunlight

Answer:
fossil fuels