A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of Vatican City. It gives a broad overview of its size and location. This follows the rule of Topic Sentence. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with 'In 1929', which needs context. Paragraph 3 starts with 'Within the city', which also needs context. Paragraph 4 starts with 'Like any other government', which refers back to something. Paragraph 5 starts with 'Now', which shows a change and needs prior information.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the information about Vatican City. It shows the current state of Vatican City and its features. This follows the rule of Summary Style.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it gives more information about Vatican City. It shows a logical order from describing the size to explaining its recognition as a state.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it continues to describe Vatican City. It logically follows the recognition of Vatican City by showing what is inside it.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it shifts from describing the city to explaining how Vatican City operates like other governments. This shows a logical order from the physical description to its functions.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects to Paragraph 4 because it continues to explain the functions of Vatican City. It shows how Vatican City has its own systems, which is a logical next step after discussing its government.