On the average, more than half of the oil in a reservoir is left behind after a well has "gone dry," using primary recovery techniques.
a) true
b) false

A) True

Explanation:

As the primary recovery technique is a method of gas drive and is the first stage of petroleum and gas production and relies on due to the natural rise of pressure between the fields and bottom hole of the well. It is a less expensive than an advanced system of oil recovery and forces the oil to the surface.

Air pollution: “combustion results in gases such as nitrogen oxides, nitrogen dioxide and particulates. the main causes of air pollution include transport, domestic combustion and industrial processes. pollutants from these sources can cause problems in the immediate vicinity and a distance away.”

The correct answer is a)  a resource with a limited supply; it will run out.