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 who the researchers studied and gives a general idea about the group. This is an overview without details. It does not use any words that need prior context. Why other lines are not chosen? Paragraph 2 starts with "The first group" which needs context from a previous sentence. Paragraph 3 starts with "The researchers" which also needs prior information. Paragraph 4 starts with "Though all participants" which refers back to earlier ideas. Paragraph 5 starts with "Though all participants" which also refers back to earlier ideas.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the findings of the research. It summarizes the results and gives a conclusion about the participants' performance.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): This pair connects because Paragraph 2 gives details about the first group mentioned in Paragraph 1. It follows a logical order where the first sentence introduces the group and the second explains what they did.
• Pair 2 (Paragraph 2 → Paragraph 3): This pair connects because Paragraph 3 continues the story of the tasks. It shows what the researchers did next after the tasks were given. This is a logical order of events.
• Pair 3 (Paragraph 3 → Paragraph 4): This pair connects because Paragraph 4 explains what happened after the researchers checked in. It shows the next step in the process, which is a logical order.
• Pair 4 (Paragraph 4 → Paragraph 5): This pair connects because Paragraph 5 gives the results of the task. It explains what the researchers found after measuring the working memory. This shows a cause and effect relationship.