A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of street food as a global phenomenon. It does not need any other sentence for context. It gives a broad overview of street food's importance. Why other lines are not chosen? Paragraph 2 starts with 'Initially,' which shows it is not independent. Paragraph 3 starts with 'Over time,' which also shows it is not independent. Paragraph 4 starts with 'As a result,' which means it needs a previous sentence for context.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the ideas about street food. It shows the final importance of street food in culture and gastronomy.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it gives a specific example of street food's history. This follows the Broader to Specific Strategy.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 continues the idea from Paragraph 2 by showing how street food changed over time. This follows the Logical Order rule.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it shows the result of street food's popularity. This follows the Cause and Effect Relationship rule.