A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of Eric the Red landing in Greenland. It gives a clear starting point for the story. It does not use any words that need prior context. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with 'He', which is a pronoun and needs context. Paragraph 3 talks about a settlement but does not say who started it. Paragraph 4 mentions the island but does not connect to a specific event without prior information.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the story. It gives the final information about the island and shows how it changed over time.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the story of Eric the Red. It uses a logical order as it tells what happened after he landed.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 follows Paragraph 2 because it talks about the settlement that started after Eric returned. This shows a cause and effect relationship.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it talks about what happened to the island after the settlement ended. This shows a logical order of events.