First sentence: Why this is the first line? This paragraph is the first because it introduces the main topic of science and technology. It gives a broad overview of how these areas affect society. It does not use any words that need prior context. Why other lines are not chosen? Paragraph 2 starts with "There is" which does not stand alone. Paragraph 3 uses "This explosion" which refers back to something not yet mentioned. Paragraph 4 starts with "Now, for the first time" which suggests a prior context.

Concluding sentence: Why this is the last line? This paragraph is the last because it wraps up the ideas presented before. It shows the final outcome of the changes in society and gives a hopeful view of the future.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it explains the result of the changes mentioned in Paragraph 1. The phrase "as a result" shows this link.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 follows Paragraph 2 because it gives more details about the explosion mentioned in Paragraph 2. The word "This" refers back to the "explosion" in Paragraph 2.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it shows the positive outcome of the explosion discussed in Paragraph 3. The phrase "Now, for the first time" indicates a new perspective that comes from the changes.