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 how language helps many human activities. This is 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 'In particular,' which is a conjunction. Paragraph 3 starts with 'But,' which is also a conjunction. Paragraph 4 uses 'It was,' which needs more context. Paragraph 5 starts with 'Now,' which suggests a continuation of thought.

Concluding sentence: Why this is the last line? This paragraph is the last line because it wraps up the main idea. It shows the outcome of the previous points about language and music. It gives a clear conclusion to the text.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it gives more detail about the type of language mentioned. This follows the Broader to Specific Strategy.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it shifts the focus to the challenges of describing music. This shows a Logical Order of ideas.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it explains how musical notation helps to solve the problem mentioned. This shows a Cause and Effect Relationship.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects with Paragraph 4 because it shows the result of having musical notation. This follows the Cause and Effect Relationship.