Answer:
scarcity
tradeoffs
Explanation:
Humans have unlimited wants and the resources available to satisfy this wants are limited. Thus, humans have to choose the most important wants and give up less important wants.
For example, if you have $20 and you want to buy a textbook , ice-cream or jeans. Each cost $20. If you need the textbook to study for a test, you would choose the book. Here $20 is the scarce resource. jeans and ice cream are what you traded off