How has air pollution contributed to the decline in caribou populations?

It has destroyed some of the lichens they feed on.

Explanation:

the correct answers are as followed:

1) to express a political opinion about an issue or event. - people who create these cartoons use their artistic ability to show where they stand on important issues in society.

2) to persuade citizens to adopt a certain belief. - political cartoons are usually critical of a policy/event that has taken place. their goal in this criticism is to get the reader to see their side of the story and to agree with it.

3) entertain readers by using humor.- often times, political cartoons are supposed to be entertaining for the reader.

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the answer to number 5 is fort sumter