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, which is sourdough baking. It gives a broad overview of the subject without going into details. This follows the rule of Topic Sentence. Why other lines are not chosen? The other paragraphs are not chosen because they do not meet the criteria for being independent. For example, Paragraph 2 starts with 'The process begins,' which makes it dependent on prior context. Paragraph 3 starts with 'Maintaining the starter,' which also needs context. Paragraph 4 starts with 'The result is,' which refers back to something not yet introduced.

Concluding sentence: Why this is the last line? This paragraph is the last line because it summarizes the outcome of the sourdough baking process. It wraps up the main ideas and reflects the overarching theme of the text, following the Summary Style rule.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 logically connects with Paragraph 1 because it continues the topic of sourdough baking. This follows the Logical Order rule, as it explains the first step in the sourdough baking process.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it explains what happens after cultivating the starter. This follows the Object Subject Strategy, where the object of Paragraph 2 (the starter) becomes the subject of Paragraph 3.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it describes the outcome of maintaining the starter. This follows the Cause and Effect Relationship rule, as the daily feedings lead to the final result of the loaf.