A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first line because it introduces the main topic of the text. It sets the scene for the lessons about riding a bike. It does not use any pronouns or definite articles that refer to previous information. Why other lines are not chosen? Paragraph 2 starts with "Encouragement" which is not a general statement. Paragraph 3 starts with "I feel" which uses a pronoun. Paragraph 4 starts with "The thrill" which uses the definite article "the" and assumes prior knowledge.

Concluding sentence: Why this is the last line? This paragraph is the last line because it wraps up the story. It shows the final achievement after all the lessons and attempts. It reflects the main theme of learning to ride a bike.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the story of learning to ride a bike. The first paragraph talks about going to the park, and the second talks about the help received. This shows a logical order of events.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it shows the result of the encouragement. The help from the sibling leads to learning more about balance and control. This is a cause and effect relationship.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it shows the outcome of the learning process. After many attempts, the result is the thrill of balancing on two wheels. This shows a logical order of progression.