A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it asks a question about the importance of knowing animal populations. It introduces the main topic without needing other sentences for context. 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 'People kill...' which is not a general statement. Paragraph 3 starts with 'Therefore...' which shows it is linked to a previous idea. Paragraph 4 starts with 'Also...' which indicates it adds to something before.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it gives a final point about animal populations. It wraps up the discussion by showing another consequence of large populations. This follows the Summary Style.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it gives a reason for the question. It shows a specific example of why knowing animal populations is important. This follows the Broader to Specific Strategy.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it explains the need to know about populations. It shows the result of killing too many animals. This follows the Cause and Effect Relationship.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it adds another reason why knowing populations is important. It shows a different effect of large populations. This follows the Logical Order.