First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of cartography. It gives a broad overview of what cartography is. It does not use any words that need prior context. Why other lines are not chosen? Paragraph 2 starts with 'Therefore,' which is a conjunction. Paragraph 3 starts with 'Early maps,' which is not general and needs context. Paragraph 4 also starts with 'Therefore,' which is a conjunction.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion about maps. It summarizes how modern maps are made and reflects on the overall theme of cartography.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it continues the topic of cartography. It explains what early maps were like, which is a specific detail about the historical background.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it shows a change in map-making. It explains how maps changed during the Age of Discovery, which follows the idea of early maps.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it shows the result of the changes in map-making. It explains how modern maps are made, which is a logical next step after discussing precise measurements.