economics is the study of resources. these resources include natural, and capital goods.
1. limitless, land
2. scarce, human
3. infinite, machinery

2. scarce, human

Explanation:

Economics is the study of scarce resources. These resources include natural, human, and capital goods.

The reason why economics studies scarce resources is because human wants are infinite and the resources to satisfy human's are scarce. So, economics have to teaches us how to allocate scarce resources when we have them in our possession.  These resources include natural, human, and capital good.  

answer; how many employees will be needed for jobs in the coming period;