Final answer:
China's isolation from other civilizations was chiefly due to physical barriers such as the Gobi and Taklamakan deserts, and the Himalayan and Hindu Kush Mountains. These geographical barriers prompted distinct cultural and political developments within China and affected the historical interactions with nomadic peoples.
Step-by-step explanation:
One significant reason that China was isolated from influences by other civilizations was because it had physical barriers such as the Gobi and Taklamakan deserts, and the Himalayan and Hindu Kush Mountains. Therefore, the correct answer is (a) Physical.
China's diverse geography, which includes massive deserts like the Taklamakan, known for its harshness with a saying that translates to "You will go in but you will not go out," and formidable mountain ranges like the Himalayas, has historically acted as a natural deterrent to interaction with neighboring regions. These geographical barriers contributed to China's isolated development, influencing its distinct culture and political systems. Over time, these physical features also posed challenges for agrarian societies and required adaptation and innovation to support population growth and maintain national defense.
In the context of relationships with neighboring civilizations, China often found itself having to defend its borders against the nomadic peoples of the steppes. Defensive structures like The Great Wall of China were erected, yet the nomads were proficient at navigating the challenging terrains with their superior horsemanship, often circumventing such defenses. This dynamic led to a complex historical interaction between China's settled societies and the mobile cultures surrounding them.