What did Rome use to improve trade, collect taxes, and pay soldiers?

Explanation:

An empire of trade

125 AD. Roman transport in this era was based on sea routes and roads. Trade was made simpler by the use of a single Roman currency.

Tax farmers (Publicani) were used to collect these taxes from the provincials. Rome, in eliminating its own burden for this process, would put the collection of taxes up for auction every few years. ... These payments were, in effect, loans to the state and Rome was required to pay interest back to the Publicani.

Roman soldiers were partly paid in salt.

hello there!

the graphics that you have attached within the question, indicates that few people in bolivia work in industry according to its labor force.

however, the graphic that is on the right side of the picture shows the gdp sector in bolivia. this gross domestic product is a macroeconomic magnitude   that shows the monetary value of all finished goods and services within a country's borders in a specific time period. in this case, the graphic is showing the monetary value in each sector -agriculture, industry and services- of bolivia in 2012.

so, although the first graphic located at the left side indicates that not so many people work in industry, this is the second most important sector according to the gdp metrics because of the monetary value that impacts on its country. it does not need to be the most valuable one. if it makes an impact on the country's economy, it will be definitely crucial to it.

c. troops marched forward in close formation against newer, more accurate weapons