What kinds of goods did the ming treasure ships bring back to china?

a. exotic objects and animals to fill the emperor's palace and gardens

b. new farming techniques and equipment

c. staple foods such as rice, wheat, and barley

d. new kinds of weapons and explosives

From 1405 until 1433, the Chinese imperial eunuch Zheng He led seven ocean expeditions for the Ming emperor that are unmatched in world history. These missions were astonishing as much for their distance as for their size: during the first ones, Zheng He traveled all the way from China to Southeast Asia and then on to India, all the way to major trading sites on India's southwest coast. In his fourth voyage, he traveled to the Persian Gulf. But for the three last voyages, Zheng went even further, all the way to the east coast of Africa

The dangers of an inadequate monetary supply.