Champa Rice, a tribute gift from Vietnam to China, led to which demographic change in China?

• A. Population decline
• B. Urban overcrowding
• C. Agricultural stagnation
• D. Population increase

Answer: (D)

The key idea is how a breakthrough in agriculture can drive people’s size and distribution. Champa rice was a high-yield, fast-maturing variety that China adopted after receiving it from Vietnam. Because it could produce more grain—and in many places could be harvested more than once a year with good irrigation—overall food production rose significantly. More reliable and abundant food means the land could support a larger population, reducing famine risk and enabling population growth over time. That’s why the demographic change associated with Champa rice is a population increase. Exhaustive food shortages or stagnation wouldn’t fit with a boost in yields, and while more people can lead to urban growth later, the immediate and direct consequence described here is a growing population.