A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of Babylon and its beauty. It gives a broad overview of the city and its historical context. This follows the rule of Topic Sentence. Why other lines are not chosen? Other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with "Its" which is a pronoun and needs context. Paragraph 3 starts with "These" which also needs prior information. Paragraph 4 starts with "The" which assumes knowledge of the subject. Paragraph 5 starts with "Water" which does not introduce the main topic. Paragraph 6 starts with "It" which refers back to something not yet mentioned.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it provides additional information about the gardens. It wraps up the topic by explaining who wanted the gardens built. This follows the Conclusive Words strategy, as it gives a final thought about the gardens.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the topic of Babylon. It uses the Broader to Specific Strategy. The first sentence talks about the beauty of Babylon, and the second sentence gives a specific example of this beauty, which is the hanging gardens.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it gives more detail about the hanging gardens. This follows the Broader to Specific Strategy. The second sentence mentions the gardens, and the third sentence explains how they were built.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it describes what was done to the gardens. This uses the Logical Order strategy. The third sentence talks about the structure of the gardens, and the fourth sentence explains how they were decorated.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects to Paragraph 4 because it explains how the gardens were maintained. This follows the Cause and Effect Relationship strategy. The fourth sentence describes the gardens, and the fifth sentence explains how they were watered.