A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first line because it introduces the main topic. It talks about researchers going to Gabon and their purpose. This is a clear topic sentence. It sets up the main idea without going into details. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with "Only things didn't exactly go as planned," which needs context. Paragraph 3 starts with "The elephants noticed the drones," which also needs the previous information. Paragraph 4 starts with "And it wasn’t just that the elephants noticed them," which is not independent. Paragraph 5 starts with "Some of them took off running," which also needs context.

Concluding sentence: Why this is the last line? This paragraph is the last line because it describes the final actions of the elephants. It wraps up the story by showing what happened after the elephants noticed the drones.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): This pair connects because Paragraph 2 shows the result of the actions in Paragraph 1. The phrase "Only things didn't exactly go as planned" shows that there was a problem after the researchers' plans.
• Pair 2 (Paragraph 2 → Paragraph 3): This pair connects because Paragraph 3 explains what went wrong. The elephants noticing the drones is a direct result of the plans not going well.
• Pair 3 (Paragraph 3 → Paragraph 4): This pair connects because Paragraph 4 gives more detail about the elephants' reaction. It shows that the elephants were not just aware of the drones, but they were also upset.
• Pair 4 (Paragraph 4 → Paragraph 5): This pair connects because Paragraph 5 shows the actions of the elephants. It explains what happened next because they were agitated.