Answer:
b. they built an irrigation system for farming.
Explanation:
The irrigation system is something big and permanent, made by populations that decided to stabilize and live in the region where the irrigation system was established. This is because, this population wants to start agricultural activities and plant crops that need long times (often) to generate food. In other words, the implantation of an irrigation system means the establishment of agriculture, which is a common characteristic of the population that does not intend to change regions.
In this regard, historians know that the settlers of San Antonio de Bexar intended to make it a permanent settlement because they implemented an irrigation system in the region.
“Productivity means Quantity of output produced by one unit of production input in a unit of time. ... Productivity and economic growth are closely linked because economic growth occurs when productivity increases to allow for such growth.”
The law of supply states that as the prices go up the demand goes down