1. F
2. B Explanation: The origins of the Iditarod are a matter of public record. However, someone who never heard of the race could easily question its claim to fame.
3. F
4. O
5. B Explanation: The phrase "one and only" injects a personal opinion into the sentence.
6. F
7. F
8. B Explanation: The phrase "widely considered" suggests that the status of the record could be a cause for disagreement.
9. F Explanation: Salsa does indeed outsell ketchup, but not everyone would agree that this fact is "a sign of the times."
10. F