A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it starts with "To start," which shows it is an introduction. It talks about checking the vehicle first, which is a good beginning for maintenance. Why other lines are not chosen? The other paragraphs do not work as the first sentence. For example, Paragraph 2 starts with "Regular oil changes," which is not an introduction. Paragraph 3 starts with "Checking the tyre pressure," which is also not an introduction. Paragraph 4 starts with "Finally," which shows it is not the first sentence.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it uses the word "Finally," which shows it is wrapping up the ideas. It also talks about tracking the car's health, which is a good way to end the discussion on vehicle maintenance.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the idea of vehicle maintenance. The phrase "Regular oil changes" follows the visual inspection, showing the next step in taking care of the vehicle.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it talks about another important maintenance task. The idea of checking the tyre pressure follows the oil changes, showing another way to keep the vehicle running well.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it talks about the next step after checking the tyres. Keeping a record of maintenance helps you remember what you have done, which is important after checking the tyres.