A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main idea. It talks about how brains can be trained, which sets the topic for the rest of the text. 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. - Paragraph 2 starts with 'For example,' which is a connector. - Paragraph 3 starts with 'It's the same with studying,' which needs context. - Paragraph 4 starts with 'Once you develop,' which also needs context.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the main idea. It shows the result of having a good study routine. This follows the Conclusive Words rule.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it gives an example of how to train the brain. This follows the Broader to Specific Strategy.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it shows that studying is similar to reading. This follows the Logical Order rule.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it explains how a good study routine helps studying. This follows the Cause and Effect Relationship rule.