Instructions: Choose One Answer from Each Pair of Selections

Q14: A city is located at sea level.

Q15: Human-induced pollution enters the atmosphere from both

Q16: Instructions: Choose one answer from each pair

Q17: HFCs and HCFCs are _.<br>A) the primary

Q18: On clear, cold winter nights, cities tend

Q20: Photochemical smog _.<br>A) only forms at night<br>B)

Q21: Which substance is considered a primary pollutant?<br>A)

Q22: Which gas is a major source of

Q23: Instructions: Choose one answer from each pair

Q24: Which pollutant is formed during the incomplete