A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic. It tells us what the researchers did with the volunteers. It does not need any other sentence for context. It is a general statement about the tasks. Why other lines are not chosen? Paragraph 2 starts with 'Throughout' which is a transitional word. This means it connects to something before it. Paragraph 3 starts with 'At the end', which also suggests it follows something else. Paragraph 4 is not independent because it starts with 'Scored by', which needs more information to make sense.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it gives the final detail about the scoring. It wraps up the information about the tasks and how the participants were evaluated. It does not need more information to make sense.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the idea of the tasks. The phrase 'Throughout the tasks' shows that it is about what happened during the tasks mentioned in Paragraph 1. This is a 'Logical Order' connection.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 follows Paragraph 2 because it talks about what happened after the tasks. The phrase 'At the end' shows the order of events. This is a 'Chronological Order' connection.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it explains how the participants were scored. The phrase 'Scored by' shows that it gives more detail about the measurement mentioned in Paragraph 3. This is a 'Broader to Specific Strategy' connection.