You are presented with the quiz "what causes the immune system to not work properly?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "immunodeficiency occurs when the immune system is not working properly" and "hIV, the human immunodeficiency virus, is a retrovirus". So, what's the best answer to the question?
OPTIONS:
- HIV
- lack
- DDT
- p53
- antibiotics
- h2o
- memory cells
- HPV

Answer: HIV

You are presented with the quiz "What usually occur in genes that control the cell cycle?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "mutations that lead to cancer usually occur in genes that control the cell cycle" and "cancer is an example of a mutation in cells". So, what's the best answer to the question?
OPTIONS:
- Leptospirosis
- competition
- A Greek letter
- a mutation in cells
- Plant reproduction
- biological diversity
- resistance
- resistance activities

Answer: a mutation in cells

You are presented with the quiz "what does hitting an object cause?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "hitting an object causes the particles in that object to vibrate" and "by it's nature, a vibration is a frequency wave ". So, what's the best answer to the question?
OPTIONS:
- frequency waves
- harmful substances
- Electrical energy
- chemical reaction
- friction
- Movement
- heat energy
- chemical changes

Answer:
frequency waves