Answer the following question: Fact 1: The emission of sulfur dioxide causes acid rain. Fact 2: Polluted rain is called acid rain . Given the two facts above, what causes pollution in rain?

1. sulfur dioxide; 2. carbon dioxide; 3. nitrogen; 4. contamination; 5. smog; 6. hydrogen; 7. fossil fuels; 8. flooding;
Answer:
1.