Why are trade barriers necessary for protecting employment​

The objective of trade protectionism is to protect a nation's vital economic interests such as its key industries, commodities, and employment of workers. Free trade, however, encourages a higher level of domestic consumption of goods and a more efficient use of resources, whether natural, human, or economic

You not be doing this in a quiz. if you actually studied your work you would know the answer. the answer though is that they would use gdp per capita because it measures a smaller portion (person). this could show individual growth per person in the country.