First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic. It gives a broad overview of the changes happening on Earth. It does not use any specific details or references to other sentences. Why other lines are not chosen? Paragraph 2 starts with 'People' which is a pronoun and needs context. Paragraph 3 starts with 'For example' which shows it is not independent. Paragraph 4 starts with 'Furthermore' which is a conjunction and needs a previous sentence for context.

Concluding sentence: Why this is the last line? This paragraph concludes the text by providing a final example of how the earth is changing. It wraps up the ideas presented in the previous paragraphs.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): There is a logical order here. The first sentence talks about changes on Earth. The second sentence explains how people and machines are part of these changes. This shows a clear flow of ideas.
• Pair 2 (Paragraph 2 → Paragraph 3): The second sentence gives a general idea about reshaping the land. The third sentence provides specific examples of how this is done, showing a General→Specific progression.
• Pair 3 (Paragraph 3 → Paragraph 4): The third sentence gives examples of roads. The fourth sentence continues with another example of how the land is reshaped, which is the construction of dams. This shows a logical order of examples.