Which of the following is an example of an emotional appeal?
a. many organizations have offered recommendations.
b. it will have global impact in the near future.
c. it will be the greatest environmental tragedy.
d. more than 90 percent of the scientists agreed that it is probable

1. C (see that word "tragedy"? doesn't your heart stop just reading it? that's emotion.) 
2. A (how come no one else gets this? a scientific study is evidence; you can't introduce evidence from any of the other choices, there is no doubt, the numbers are all that matters) 
3. This is a tossup but I would guess "to persuade" C. I love to laugh, yes, it's entertaining. But humor is strongly persuasive. You get someone laughing and it's most of the battle. They already agree with you; they just don't realize it.

Clean air provides nitrogen