If there is no world trade. This is not the world, and life is difficult because there is no exchange of knowledge and ideas, including the resources of individual countries.
If the world No international trade. This world is not worth living and it would be difficult because there is an exchange of knowledge and ideas, including resources of each country.
If this world no international trade. This world is not live and life should be difficult because there is no knowledge exchange ideas, including the resources of each country.