First sentence: Why this is the first line? This paragraph is the first because it introduces the main topic. It talks about Johannes Gutenberg and his invention of the printing press. This is a general statement that does not need other sentences for context. It sets the stage for the rest of the text. Why other lines are not chosen? Paragraph 2 starts with "This invention" which refers back to the printing press, so it cannot be first. Paragraph 3 starts with "As a result" which shows it depends on earlier information. Paragraph 4 starts with "Besides" which also shows it connects to previous ideas.

Concluding sentence: Why this is the last line? This paragraph is the last because it wraps up the ideas. It shows the final effect of the printing press, which is that knowledge became more accessible. This gives a complete view of the topic.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it uses the word "This invention". This shows it talks about the printing press. This is a clear link between the two sentences.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 with the phrase "As a result". This shows that the rise in literacy rates is a direct effect of the mass production of books. This is a cause and effect relationship.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 with the word "Besides". This shows that the increase in literacy is linked to more knowledge being available. It adds more information about the effects of the printing press.