First sentence: Why this is the first line? This paragraph is the first sentence because it asks a question about travel. It introduces the main topic of travel. This is a general statement that does not need other sentences for context. It does not start with a conjunction or use pronouns. Why other lines are not chosen? The other paragraphs are not chosen because they do not meet the criteria for being independent. For example, 'Some TV programs will show tourist attractions' starts with a specific subject and does not introduce the main topic. 'People can see the outside world through satellites' and 'They can also observe them through other activities' are specific statements that follow the first sentence.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the ideas about observing the world. It gives a final thought on how people can see things.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it gives an example of why people travel. The question in Paragraph 1 leads to the answer in Paragraph 2.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it explains how people can see the world. The idea of seeing attractions on TV leads to seeing the world through satellites.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it continues the idea of observing the world. It shows another way to see the outside world.