A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first line because it introduces the main topic of the text. It talks about a new technology that helps us understand sleep in animals. It does not need other sentences to make sense. It gives a broad overview of the subject. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with "Three-toed sloths," which needs the first paragraph for context. Paragraph 3 starts with "And male sandpipers," which is a continuation and needs a previous sentence. Paragraph 4 starts with "Now," which shows it is not independent and needs earlier information.

Concluding sentence: Why this is the last line? This paragraph is the last line because it wraps up the discussion. It shows ongoing research related to the topic of sleep in animals. It gives a conclusion about how the technology is being used to study sleep further.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it gives a specific example of the general idea in Paragraph 1. This follows the Broader to Specific Strategy. The first paragraph talks about sleep in animals, and the second paragraph gives a specific case of sloths.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it continues to talk about sleep in animals. It uses the Connector strategy with "And" to show that it adds more information about different animals and their sleep habits.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it continues the topic of sleep in animals. It uses the Object Subject Strategy, where the subject of sleep in animals moves to a new subject about research on wallabies, showing a logical flow.