Which resource was so valuable that it aided the growth of kingdoms by becoming a form of currency and a major source of political power?
a. coffee beans
b. glass
c. copper
d. salt

Copper was the resource that was so valuable that it aided the growth of kingdoms by becoming a form of currency and a major source of political power. The answer is letter C. Copper used was 10000 years old and discovered at the Middle East in 9000BC.

the population grew a lot and was making more money