A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of jet lag. It gives a clear idea of what the text will discuss. It does not need any other sentence for context. It does not use any pronouns or definite articles that refer to previous ideas. Why other lines are not chosen? Paragraph 2 starts with "It's" which is a pronoun and needs context. Paragraph 3 starts with "It's also why" which also uses a pronoun. Paragraph 4 starts with "But" which is a conjunction. Paragraph 5 starts with "You can" which is not general enough to be independent.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it provides a solution to the problem of jet lag. It wraps up the discussion by giving practical advice. It does not need any more information after it.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it explains what jet lag is. This is a logical order where the first paragraph introduces the topic and the second paragraph gives more details about it.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it gives examples of how jet lag affects people. This shows a broader to specific strategy where the second paragraph gives a general idea and the third paragraph provides specific examples.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it offers a positive note after discussing the effects of jet lag. The word "But" shows a contrast between the negative effects and the idea that jet lag can be managed.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects to Paragraph 4 because it gives solutions to manage jet lag. This shows a logical order where the fourth paragraph states a problem and the fifth paragraph offers a way to solve it.