A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic, which is the Dead Sea. It gives a broad overview of the lake's significance by stating its position as the lowest lake in the world. This follows the rule of Topic Sentence. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone as the first sentence. For example, Paragraph 2 starts with 'It contains,' which uses a pronoun and does not introduce the topic. Paragraph 3 starts with 'It contains,' which also uses a pronoun. Paragraph 4 starts with 'The salt,' which does not introduce the main topic. Paragraph 5 starts with 'The lake,' which is not independent. Paragraph 6 starts with 'It has,' which uses a pronoun.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the information about the Dead Sea by providing specific details about its size. This follows the Summary Style rule, as it brings together the earlier points about the lake.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it continues to explain more about the Dead Sea. This follows the Logical Order rule, as it gives more details about the lake's water.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it explains what happens to the water in the Dead Sea. This follows the Cause and Effect Relationship rule, as it shows the result of the high salt content.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it talks about the effect of the salt on swimming. This follows the Logical Order rule, as it shows how the salt affects swimmers.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects with Paragraph 4 because it gives more information about the location of the Dead Sea. This follows the Topical Order rule, as it shifts from discussing the salt to the lake's position.
• Pair 5 (Paragraph 5 → Paragraph 6): Paragraph 6 connects with Paragraph 5 because it provides more details about the size of the lake. This follows the Broader to Specific Strategy, as it gives specific measurements after stating the location.