5. The buying and selling of goods and services 6. Chlorofluorocarbons (CFCs) damage this atmospheric layer 7. The U. S., Mexico, and this country participate in NAFTA 8. Foreign is the general term for government efforts to help the poor in other countries 9. At one time, this ancient civilization controlled all of western South America between Ecuador and Chile 10. Babur, a descendant of Genghis Khan and Tamerlane, was the first emperor of this civilization in India 11. Rachel Carson wrote the book, The Silent , to warn about the contamination of the natural world caused by pesticides and other chemicals Down 1. Procurement of goods and services from an outside supplier is called 2. This civilization settled in the Valley of Mexico and founded their capital, Tenochtitlan, in 1345 3. This political, economic, and social system prevailed in medieval Europe and relied on a relationship among lords, vassals, and serfs 4. During this economic phase, people tended flocks of domesticated animals such as goats and sheep 8. The Theory of Comparative holds that countries should specialize in the goods and services where they have a relative edg