A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main idea of the text. It talks about starting the day with exercise, which is the main topic. It does not refer to any previous information. This follows the rule of Topic Sentence. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with "Moreover," which is a conjunction. This means it connects to something before it. Paragraph 3 uses "The" which assumes prior knowledge. Paragraph 4 also does not stand alone because it refers to a habit without introducing it first.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the main ideas of the text. It shows the overall benefit of the habit of exercise. This follows the rule of Summary Style, as it brings together the earlier points about mood, energy, and health.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it adds more information about the benefits of exercise. The word "Moreover" shows that it continues the idea from the first paragraph. This follows the Connector Strategy.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it explains the physical benefits of exercise. This follows the Broader to Specific Strategy, where the second paragraph gives a general idea and the third paragraph gives specific details.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it talks about how the habit of exercise helps mental health. This follows the Logical Order strategy, where the third paragraph gives evidence and the fourth paragraph shows the result.