A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first because it introduces the main topic. It tells us about the first successful flight. This is a broad overview of the event. It does not need other sentences to understand it. Why other lines are not chosen? Paragraph 2 starts with "Other people" which needs context. Paragraph 3 starts with "On 17th December" which is a specific date and needs more information. Paragraph 4 starts with "Its engine" which refers to something not yet introduced. Paragraph 5 starts with "The engine" which also assumes prior knowledge.

Concluding sentence: Why this is the last line? This paragraph is the last because it gives detailed information about the engine. It wraps up the topic by explaining how the engine works. It does not need more information after it.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it gives more information about the Wright brothers. It explains who they are and their importance. This is a logical order from a general statement to a specific detail.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it gives a specific example of the Wright brothers' success. It shows the date and details of their flight. This is a logical order from a general statement to a specific event.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it talks about the engine of the plane. It gives more details about the Flyer. This is a logical order because it continues the topic of the plane.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects to Paragraph 4 because it gives more details about the engine. It explains how the engine works. This is a logical order from a general statement about the engine to specific details about its parts.