เพราะว่าแต่ละประเทศนั้น มีทรัพยากร

Because each country. The resources are different inputs. The output of each of the countries, it varies with the. Requirements of the people in each country, it would be something exotic in what the country itself is not or is not satisfactory, but it is necessary to have international trade such as Thailand must buy crude oil from the Middle East, etc.

Because each country has the resources to different inputs. The output of each country is different, too. Product requirements of people in each country wanted something new in what country ตัวเองนั้น no or only satisfied are memory was to have international trade such as Thai to buy crude oil from the Middle East, etc.