A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of cooking an omelette. It gives a broad overview of what is needed to make a good omelette. It does not refer to any previous information. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with "It begins," which is a pronoun and needs context. Paragraph 3 uses "The key," which assumes prior knowledge. Paragraph 4 starts with "Finally," which shows it is not the first sentence.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the process of making an omelette. It shows the final action and gives a sense of completion to the cooking process.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it gives a specific action related to the general idea of cooking an omelette. This follows the Broader to Specific Strategy.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it continues to explain important steps in making an omelette. This shows Logical Order as it follows the process of cooking.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it describes the final step after discussing the heat of the pan. This follows the Chronological Order as it shows the sequence of cooking.