A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic. It describes the setting of the experiment with the child and the marshmallow. This is an introductory statement that sets the scene without needing any prior context. Why other lines are not chosen? The other paragraphs do not qualify as the first sentence. For example, Paragraph 2 starts with 'The child is told,' which uses a definite article and refers back to the child mentioned in Paragraph 1. Paragraph 3 starts with 'Kids on average,' which is not general enough to stand alone. Paragraph 4 starts with 'The longer a child can resist,' which also uses a definite article and assumes prior knowledge.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the main idea of the text. It gives a conclusion about the importance of resisting temptation. It summarizes the earlier points about the child and waiting, showing the overall theme of the study.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the story about the child. The phrase 'The child is told' shows that this is what happens next after the child is set up in the room. This is a logical order of events.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 follows Paragraph 2 because it gives information about what happens after the child is told the instructions. It shows the result of the instructions, which is that kids wait before eating the marshmallow. This is a cause and effect relationship.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it explains the importance of waiting. It shows that waiting longer is linked to better skills later in life. This is a broader to specific strategy, where the specific action of waiting leads to a general conclusion about competency.