A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first line because it introduces the main topic of chess as a metaphor for life. It does not refer to any previous information and sets the stage for the rest of the text. It uses a broad overview to explain what chess represents. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with 'Each piece,' which uses a pronoun and cannot stand alone. Paragraph 3 starts with 'Decisions made,' which is not a general statement. Paragraph 4 starts with 'The game teaches,' which uses the definite article 'the' and assumes prior knowledge. Paragraph 5 starts with 'Ultimately,' which is a transitional word.

Concluding sentence: Why this is the last line? This paragraph is the last line because it wraps up the main ideas. It uses the word 'Ultimately,' which signals a conclusion. It brings together the lessons from chess and life, showing the final thoughts on the topic.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the idea of chess as a metaphor. The phrase 'Each piece on the chessboard' shows how individual parts contribute to the whole, linking to the broader theme of strategy.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it discusses decisions in chess. The idea of individual pieces relates to the decisions made, showing how each choice affects the game and life.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it talks about the lessons learned from chess. The idea of sacrifices leads to the importance of planning and understanding consequences.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects to Paragraph 4 because it concludes the discussion about chess and life. It shows how mastering chess relates to wisdom, tying together the lessons learned from planning and consequences.