The classic Western business model was based on the economic realities of the eighteenth century. The factors of production were relatively strong: the land was immobile (although its fertility or use might change) and labour mobility was severely constrained by political constraints. For most of the century, political barriers and lack of knowledge of other markets limited cross-border capital movements. (In the mid-nineteenth century, capital and labor were freer between Europe and America.) Eighteenth-century technology was relatively simple by today`s standards and relatively similar in all countries. In addition, the production of most products at that time was subject to a decrease in yields, which meant that the increase in production increased the production costs of each additional unit. In fact, economists consider this law of comparative advantage to be fundamental. As Dominick Salvatore says in his basic economics textbook International Economics, the law of comparative advantage “remains one of the most important and still undisputed laws of economics. The law of comparative advantage is the cornerstone of pure international trade theory.  Most economists today regard the law of comparative advantage as one of the fundamental principles of economics. However, some very important reservations about the law of comparative advantage are often overlooked or embellished. Kei-Mu Yi of the World Bank notes that standard economic models were very well responsible for the expansion of world trade until the mid-1970s, but cannot explain the growth of trade since then.
 However, a model that takes into account supply chains explains the growth of trade and estimates that such vertical specialization now accounts for about 30% of world trade. The reason for these significant deviations from the original model is that the modern world of free trade is so different from the original historical environment of free trade models. Today, no one clearly determines the best economic outcome on the basis of natural national advantages. The current world economy does not highlight a single better result achieved through international competition in which each country serves the best interests of the world by producing precisely the goods it is obviously the most efficient to produce. On the contrary, there are many possible outcomes that depend on what countries actually do, on the skills, natural or man-made, that actually develop them.  In Africa, epAs support the implementation of the Africa-Europe Alliance for Sustainable Investment and Jobs, launched in September 2018. They are key instruments of the EU`s global strategy for Africa. The economic pillar of this strategy identifies trade – in addition to regional and continental economic integration – as an important element in promoting the sustainable development of African countries. .