First sentence: Why this is the first line? This paragraph is the first because it introduces the main topic. It talks about the invention of the wheel, which is the main idea of the text. It does not need any other sentence to understand it. This follows the rule of Topic Sentence. Why other lines are not chosen? Paragraph 2 starts with 'This innovation', which needs the previous sentence for context. Paragraph 3 starts with 'The increased efficiency', which also needs earlier information. Paragraph 4 starts with 'As trade routes expanded', which needs prior context. Paragraph 5 starts with 'Ultimately', which suggests it is not the beginning.

Concluding sentence: Why this is the last line? This paragraph is the last because it wraps up the main idea. It shows the overall impact of the wheel on human civilization. This follows the rule of Conclusive Words.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it explains what the invention of the wheel led to. This follows the Logical Order rule.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it shows the result of the faster movement of goods. This follows the Cause and Effect Relationship rule.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it explains what happened as trade routes expanded. This follows the Logical Order rule.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects to Paragraph 4 because it summarizes the overall impact of the wheel. This follows the Topic Closure rule.