A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic about AI and drug discovery. It does not refer to any previous information. It sets the stage for what will follow. Why other lines are not chosen? Paragraph 2 starts with "In 2020," which shows a specific time and assumes prior knowledge. Paragraph 3 starts with "In 2021," which also assumes prior context. Paragraph 4 starts with "Based on the track record," which refers to past events and is not independent.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion. It gives a prediction based on the earlier points. It summarizes the ideas about AI and drug discovery.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the discussion about AI in drug discovery. It uses a logical order, moving from the hype to a specific example of AI in action.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 logically follows Paragraph 2 because it gives another example of Exscientia's work. It shows a chronological order, moving from one year to the next.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it looks forward based on the past examples. It uses a cause and effect relationship, predicting future discoveries based on what has happened.