A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first line because it introduces a significant event, the Irish potato famine, and its impact. It sets the stage for the discussion about population changes. It provides a clear overview without needing prior context. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with 'Prior to the potato blight,' which needs context. Paragraph 3 mentions a specific time but does not connect to the famine. Paragraph 4 talks about the potato crop but does not introduce the main topic. Paragraph 5 starts with 'However,' which shows a continuation of thought.

Concluding sentence: Why this is the last line? This paragraph is the last line because it wraps up the discussion about population changes. It shows the result of the events discussed in the previous paragraphs. It provides a clear conclusion to the topic.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): This pair connects because Paragraph 2 explains a concern before the famine. It shows a logical order from the effects of the famine to the issues that led to it.
• Pair 2 (Paragraph 2 → Paragraph 3): This pair connects because Paragraph 3 gives details about population growth. It follows logically from the concern of overpopulation mentioned in Paragraph 2.
• Pair 3 (Paragraph 3 → Paragraph 4): This pair connects because Paragraph 4 explains why the population grew. It follows the general statement about population in Paragraph 3 with specific reasons.
• Pair 4 (Paragraph 4 → Paragraph 5): This pair connects because Paragraph 5 shows the negative effect of the failed crop. It follows logically from the previous paragraph about the benefits of the potato crop.