use the list below to answer the following question: 1. improvements in technology. 2. increases in the supply (stock) of capital goods. 3. purchases of expanding output. 4. obtaining the optimal combination of goods, each at least-cost production. 5. increases in the quantity and quality of natural resources. 6. increases in the quantity and quality of human resources. which set of items in the list would shift an economy's production possibilities curve outward?