A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic. It clearly states what a geodetic datum is. This follows the rule of Topic Sentence. Why other lines are not chosen? The other paragraphs are not independent. For example, Paragraph 2 starts with 'True', which is a pronoun that refers back to something. Paragraph 3 starts with 'They', which is also a pronoun. Paragraph 4 starts with 'Prior', which suggests a time context that needs earlier information.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion about geodetic data. It gives a conclusion about past beliefs. This follows the Conclusive Words rule.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it continues the idea of geodetic datum. It explains how it is used in mapping. This follows the Logical Order rule.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it gives more specific information about geodetic data. It shows a Broader to Specific Strategy.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it gives historical context. It explains what happened before the 1700s. This follows the Chronological Order rule.