[CHAPTER 11 – Alternatives to Fossil Fuels]  The mass number of an atom is the _______

[CHAPTER 11 – Alternatives to Fossil Fuels]  A general rule says that after _____half-lives, radioactive material has decayed enough to be rendered safe.

[CHAPTER 10 – Air Quality and Climate Change] The goal of the 2016 Paris Agreement is to keep climate warming well below which threshold?

[CHAPTER 10 – Air Quality and Climate Change] Why are particles smaller than 2.5 µm the most dangerous?

[CHAPTER 10 – Air Quality and Climate Change] Which of these can be used by scientists to estimate past climates?

[CHAPTER 9 – Conventional Energy: Fossil Fuels] How do oil and natural gas occur in formations?

[CHAPTER 10 – Air Quality and Climate Change] How does climate change affect alligators?

[CHAPTER 11 – Alternatives to Fossil Fuels]  The EPA considers which type of energy to be one of the most efficient heating and cooling systems?

[CHAPTER 10 – Air Quality and Climate Change] One of the first environmental laws passed in the United States to regulate pollution was the ___________

[CHAPTER 9 – Conventional Energy: Fossil Fuels] Where are the largest conventional oil and natural gas reserves in the world found?