A.I. Explanation:

First sentence: Why this is the first line? This paragraph introduces the main topic about Everest and its history. It starts with a strong statement about fossilized fish remains, which is interesting and grabs attention. This is a general statement that does not need other sentences for context. It does not use conjunctions or pronouns that refer to other ideas. Why other lines are not chosen? Paragraph 2 starts with "About 200 million years ago," which is a specific time reference and needs context. Paragraph 3 starts with "One of the Tibetan names..." which refers to a specific name and needs prior knowledge. Paragraph 4 starts with "Mapping the Himalayas..." which is a continuation of thought and does not stand alone.

Concluding sentence: Why this is the last line? This paragraph concludes the text by explaining the challenges of mapping Everest. It wraps up the discussion about Everest's history and the difficulties faced in understanding it. It does not introduce new ideas but summarizes the situation.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): This pair connects because the first paragraph raises a question about how Everest was formed. The second paragraph answers this question by explaining the geological history of the Indian subcontinent and its collision with Asia. This shows a logical order from question to explanation.
• Pair 2 (Paragraph 2 → Paragraph 3): This pair connects because the second paragraph describes how the mountain was formed, and the third paragraph gives a name and history of the mountain. This shows a broader to specific strategy, moving from the general formation of the mountain to specific details about its name.
• Pair 3 (Paragraph 3 → Paragraph 4): This pair connects because the third paragraph talks about the name and measurement of Everest, and the fourth paragraph explains the challenges in mapping it. This shows a logical order from the history of the mountain to the difficulties faced in understanding it.