A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of the text. It talks about the resurgence of interest in analogue photography, which sets the stage for the following paragraphs. 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. For example, Paragraph 2 starts with 'This revival,' which needs context from a previous sentence. Paragraph 3 starts with 'Developing film,' which also needs context. Paragraph 4 starts with 'The grain,' which refers to something mentioned before. All these sentences are dependent on prior information.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion about film photography. It summarizes the qualities that make film special. This follows the Summary Style rule.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it explains what the revival is about. This follows the Broader to Specific Strategy. The first sentence gives a general idea of the resurgence, and the second sentence gives specific reasons for it.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it gives an example of what enthusiasts appreciate. This follows the Topic Example rule. The second paragraph talks about the revival, and the third paragraph explains one aspect of that revival.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it continues to discuss the qualities of film photographs. This follows the Logical Order rule. The third paragraph talks about satisfaction in developing film, and the fourth paragraph describes the qualities that give that satisfaction.