A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first line because it introduces the topic of photography in the past. It gives a broad overview of how photography used to be. It does not refer to any previous information. Why other lines are not chosen? Paragraph 2 starts with "In contrast" which is a conjunction. Paragraph 3 starts with "This shift" which uses a pronoun that refers back to something not yet mentioned. Paragraph 4 starts with "However" which is also a conjunction.

Concluding sentence: Why this is the last line? This paragraph is the last line because it wraps up the discussion about photography. It shows the negative effect of the convenience of digital photography.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 using the rule of Contrast. It shows how digital photography is different from the past methods.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 follows Paragraph 2 logically because it discusses the shift in photography. It uses the rule of Broader to Specific Strategy, moving from the ease of digital photography to the questions it raises.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 using the rule of Cause and Effect Relationship. It shows the result of the shift in photography, which is the overconsumption of images.