Answer:
Subjetive is the right answer
A pile of oil soaked logs caught on fire. The media attention it gathered came to be known as Earth Day. (That was the first Earth Day.)
Answer:
The currency was unified to ensure everyone could and would pay taxes.
Explanation:
As Rome conquered new lands they brought their currency with them. When other people started using the currency it increased Rome's control and ensured everyone could easily pay taxes. It also increased trade in the regions conquered.