Part I: Understanding Details: Read the following passage and answer the questions that follow.
Passage:
The Great Wall of China was built over several dynasties to protect Chinese territories from invasions. While sections of the wall date back to the 7th century BC, most of what remains today was constructed during the Ming Dynasty (1368–1644). The wall stretches over 13,000 miles and includes watchtowers and fortifications.
What was the primary purpose of the Great Wall of China?