Question: Choose your answer.

Materials such as carbon and nitrogen go through cycles. The cycling of nitrogen waste materials is mostly dependent upon the role of which factor?

OPTIONS:
- atmosphere
- bacteria
- sunlight
- trees
My Answer: bacteria

Question: Choose your answer.

Sodium bicarbonate (NaHCO_{3}) is commonly known as baking soda. Sodium bicarbonate is a white solid that can dissolve in water. Under the proper conditions, sodium bicarbonate can release carbon dioxide (CO_{2}) gas. Which of the following is not a physical property of sodium bicarbonate?

OPTIONS:
- It is white.
- It is a solid.
- It can dissolve in water.
- It releases carbon dioxide.
My Answer: It releases carbon dioxide.

Question: Choose your answer.

Which of these will best separate iron filings from sand?

OPTIONS:
- water
- a magnifying glass
- a magnet
- rubbing alcohol
My Answer: a magnet

Question: Choose your answer.

Which stimulus causes a porcupine to extend its quills?

OPTIONS:
- lunar effect on Earth
- seasonal temperature changes
- threatening behavior by predators
- environmental encroachment by humans
My Answer:
threatening behavior by predators