Fact 1: Immunodeficiency occurs when the immune system is not working properly. Fact 2: HIV, the human immunodeficiency virus, is a retrovirus. Given the two facts above, what causes the immune system to not work properly?
OPTIONS:
- HIV
- lack
- DDT
- p53
- antibiotics
- h2o
- memory cells
- HPV

Answer: HIV

Fact 1: Mutations that lead to cancer usually occur in genes that control the cell cycle. Fact 2: Cancer is an example of a mutation in cells. Given the two facts above, what usually occur in genes that control the cell cycle?
OPTIONS:
- Leptospirosis
- competition
- A Greek letter
- a mutation in cells
- Plant reproduction
- biological diversity
- resistance
- resistance activities

Answer: a mutation in cells

Fact 1: Hitting an object causes the particles in that object to vibrate. Fact 2: By it's nature, a vibration is a frequency wave . Given the two facts above, what does hitting an object cause?
OPTIONS:
- frequency waves
- harmful substances
- Electrical energy
- chemical reaction
- friction
- Movement
- heat energy
- chemical changes

Answer:
frequency waves