If you choose between two summer jobs, what is the one you do not choose called?
question 3 options:

trade-off

opportunity cost

decision at the margin

opportunity at the margin

a is the answer i believe.

the precambrian aged rocks could be found in australia. australia is a region that has a lot of ancient civilization history from million years ago. in this region, there are a lot of recognizable fossils buried in its land which is considered a precambrian-aged rocks

answerthey are called the pampas;