input: OPTIONS:
- evaporation
- wind
- Weathering
- heat
- gasoline
- Generating heat
- friction
- hydrogen bonds Now, answer this question: Fact 1: Hydrogen bonds cause water to expand when it freezes. Fact 2: Water freezes into ice when cooled. Given the two facts above, what causes water to expand as it becomes ice?
A:
output: hydrogen bonds

Fact 1: Contact between rocks over long periods of time causes rocks to smooth. Fact 2: Because of the big wave action, the rocks are very smooth. Given the two facts above, what causes contact between rocks?

OPTIONS:
- wind
- heat
- erosion
- deltas
- waves
- motion
- seasons
- rivers

Answer: waves

Problem: OPTIONS:
- toaster
- Fuel cells
- Cooking
- a hydraulic system
- an electric stove
- oven
- refrigerator
- vacuum cleaner
Q: Fact 1: Arefrigerator is used for keeping food fresh for a long period of time. Fact 2: Fresh food is good. Given the two facts above, what appliance can keep food good a long time?
Answer: refrigerator

Problem:OPTIONS:
- the skin
- cold air
- silver
- copper
- sweating
- water
- toxins
- plastic

Fact 1: An electrical insulator slows the transfer of electricity. Fact 2: Plastic is an insulator of electricity. Given the two facts above, what slows the transfer of electricity? ?
****
A: plastic

Fact 1: Hormones are chemical messengers that control many body functions. Fact 2: Vitamins function as catalysts in chemical reactions in the body. Given the two facts above, what are chemical messengers that are catalysts in the body?
OPTIONS:
- allow growth
- acetic acid
- fibers
- photons
- fever
- hormones
- proteins
- genes
hormones

Fact 1: Many plants respond to the days growing shorter in the fall by going dormant. Fact 2: Trees are dormant from November to March. Given the two facts above, when do many trees respond to the days growing shorter?
OPTIONS:
- air cools
- Winter
- wind
- in fall
- in summer
- autumn
- late winter
- in spring

Answer:
in fall