A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic. It gives a clear overview of what the text is about: the Moai statues. It does not use any words that need prior context. Why other lines are not chosen? Paragraph 2 starts with 'Despite' which is a conjunction, so it cannot be independent. Paragraph 3 starts with 'The reason' which refers back to the topic, making it dependent. Paragraph 4 starts with 'Some theories' which also refers back to previous ideas, so it is not independent.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion. It gives theories about the Moai statues and shows that there is no agreement on the methods. This is a clear conclusion to the topic.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it continues the topic of the Moai statues. The word 'Despite' shows a contrast between their size and the fact that they were moved. This is a logical order.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it talks about the unclear reasons for the Moai statues and how they were moved. This shows a logical order from the action of moving to the questions about why and how.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it gives possible answers to the questions raised in Paragraph 3. The word 'Some theories' shows that it is providing examples of ideas related to the unclear reasons.