First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of scientific work. It uses a broad overview to set the stage for the discussion. It does not refer to any previous information, making it independent. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with 'Scientists,' which is a pronoun and needs context. Paragraph 3 uses 'This may be because,' which refers back to something not yet mentioned. Paragraph 4 starts with 'But,' which is a conjunction. Paragraph 5 starts with 'Otherwise,' which also needs prior context.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion. It shows the results of the earlier points made about scientific work and writing. It summarizes the main ideas and gives a clear conclusion.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it continues the idea of scientists and their work. The phrase 'he wrote' shows a logical order from the description of scientific work to the critique of scientists.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it explains why scientists may not get credit. The phrase 'This may be because' shows a cause and effect relationship, linking the two ideas.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it emphasizes the importance of not confusing ideas. The word 'But' shows a contrast and continues the discussion about clarity in writing.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects with Paragraph 4 because it explains the consequences of blurring the distinction. The word 'Otherwise' shows a logical order, indicating what may happen if the advice in Paragraph 4 is not followed.