A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first line because it introduces the main topic. It talks about Rosa Parks and her impact on the civil rights movement. This is a broad overview of the subject. It does not use any specific details or references to other sentences. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, 'She refused to give her bus seat to a white man' starts with a pronoun and needs context. 'The bus driver called a police officer who then arrested her' also needs context. 'Her arrest was actually planned by Martin Luther King' uses 'her' which refers back to Rosa Parks. 'King then called for a boycott on the bus system' uses 'then' which shows it is not the first idea.

Concluding sentence: Why this is the last line? This paragraph is the last line because it wraps up the story. It shows the action that followed Rosa Parks' arrest. It connects back to the impact of Rosa Parks on the civil rights movement.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): This pair connects because the second sentence gives a specific example of Rosa Parks' impact. It shows what she did that was important.
• Pair 2 (Paragraph 2 → Paragraph 3): This pair connects because the third sentence explains what happened after she refused to give up her seat. It shows the result of her action.
• Pair 3 (Paragraph 3 → Paragraph 4): This pair connects because the fourth sentence explains that the arrest was planned. It shows the reason behind the arrest.
• Pair 4 (Paragraph 4 → Paragraph 5): This pair connects because the fifth sentence shows what King did after the arrest. It shows the next step in the movement.