A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main idea of the text. It talks about the writer's interest in sustainable living and the decision to change the chairs. This is an introductory statement that sets the theme for the rest of the text. Why other lines are not chosen? The other paragraphs do not work as the first sentence. For example, Paragraph 2 starts with "Each chair" which is not general and does not introduce the main topic. Paragraph 3 starts with "The final touch" which assumes prior knowledge. Paragraph 4 starts with "Once the paint" which also assumes something has happened before.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the whole process of transforming the chairs. It shows the final action that completes the project. This gives a sense of closure to the text.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the story of transforming the chairs. It shows the first step in the process after the decision to change them. This is a logical order of actions.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 follows Paragraph 2 because it describes the next step after painting the chairs. It shows the final action needed to complete the transformation. This is a clear logical order.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it describes what happens after the final touch. It shows the last step in the process of making the chairs ready for use. This is a logical order of actions.