Economic is an essential factor to grow the population of a country. But every country have different strength and weakness industries, and also, their own natural resources. Often, countries and countries have to exchange commodities and products to fulfill the domestic needs. They may sell the strength ones to buy the lacking items. So that, the country have to develop the strength firms for making more money. And In the mean time, for keeping their weakness industries, the country does limit the importing commodities by higher tax to increase the barriers.