A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first because it introduces the main topic. It talks about the 5th century BC and the two styles of sculpture. This is a broad overview of what the text will discuss. It does not use any words that need prior context. Why other lines are not chosen? Paragraph 2 starts with "Nearly 2500 years later," which needs context from a previous sentence. Paragraph 3 starts with "One is the classical realism," which refers back to the styles mentioned before. Paragraph 4 starts with "The other is the sculpture of Africa," which also refers back. Paragraph 5 starts with "African figures in this long and vibrant tradition," which needs prior knowledge of the tradition.

Concluding sentence: Why this is the last line? This paragraph is the last because it wraps up the discussion. It shows how the styles from the past influence modern art. It gives a clear conclusion to the ideas presented in the previous paragraphs.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it shows a logical order. It talks about what happens after the 5th century BC. The phrase "Nearly 2500 years later" shows the time gap and how the styles change over time.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it explains one of the styles mentioned. It gives a specific example of one style, which is classical realism. This follows the broader idea of styles becoming rivals.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it introduces the other style. It uses the word "The other" to show that it is talking about a different style from the previous paragraph.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects with Paragraph 4 because it gives an example of how African sculpture influences modern art. It shows a logical order from discussing the style to how it affects art today.