Final answer:
The Plateau of Tibet, the Himalayas, and the Tian Shan are major geographical features located in the western and southwestern part of China. Their rugged terrain made overland trade difficult, making sea trade a more viable alternative.
Step-by-step explanation:
The Plateau of Tibet, the Himalayas, and the Tian Shan are significant physical features located in western and southwestern part of China. The Plateau of Tibet is often referred to as the 'Roof of the World', and is the highest region on earth. The Himalayas are the planet's highest mountains, located to the south of the Tibetan Plateau, and act as a natural border between China and India. The Tian Shan mountains range from the border of Kazakhstan to the northwest boundaries of China.
These features would have made sea trade more popular than overland trade due to their rugged and harsh nature. Traversing these high-altitude terrains by foot or with pack animals would be quite difficult, even dangerous. Sea trade routes, in contrast, would offer comparatively faster, safer, and more efficient means of transporting goods across long distances.
Learn more about Physical features in China