First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of GPS. It gives a clear definition of what GPS means and what it does. This is an introductory statement that sets the stage for the following information. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with 'GPS technology works,' which needs the first sentence for context. Paragraph 3 talks about the past and needs a topic to connect to. Paragraph 4 starts with 'Today,' which also needs a reference to the topic.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion about GPS. It shows how GPS is used today and gives a final thought on its importance in our lives.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it explains how GPS technology works. This is a logical order where the definition of GPS leads to its function.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it shows a contrast. It talks about how people used to find their way before GPS. This shows a change in technology.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it shows how GPS is now part of our daily lives. It continues the idea of how technology has changed the way we navigate.