A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first line because it introduces the main topic of who can issue currency. It does not need other sentences for context. It sets up the main idea without going into details. Why other lines are not choosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with 'But', which is a conjunction. Paragraph 3 uses 'the' which assumes prior knowledge. Paragraph 4 talks about a specific bank without introducing the topic first. Paragraph 5 mentions 'this lack' which needs context from earlier sentences.

Concluding sentence: Why this is the last line? This paragraph is the last line because it wraps up the discussion. It shows the result of the earlier points about currency and trade.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 using the 'Connector' strategy. The word 'But' shows a contrast between most countries and Scotland.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 follows Paragraph 2 using the 'Logical Order' strategy. It gives a specific example of the banks mentioned in Paragraph 2.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 using the 'Broader to Specific Strategy'. It gives background information about the Bank of Scotland.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 follows Paragraph 4 using the 'Cause and Effect Relationship' strategy. It explains why there was a need for better currency.