Answer: C - spiral staircase
Explanation:
During photosynthesis, plants use carbon dioxide and produce oxygen. During metabolism oxygen is used and carbon dioxide is a product. Humans impact the carbon cycle during the combustion of any type of fossil fuel, which may include oil, coal, or natural gas
Answer:
Kristin's answer is the best.
Explanation:
It is the only correct answer.
Answer: NSF International
Explanation: