1. Ricardo explains comparative advantage as the theory that even nations relatively poor at producing everything have some things they can produce relatively well. Nations should specialize in what they can produce at a lower opportunity cost and trade for the rest.
2. Before trade, Ed's grandchild had eye problems and poor vision that could not be healed without modern medicine.
3. After trade allowed global specialization and cooperation, Ed's grandchild was able to access life-saving medicine developed by Merck and have good vision, now doing homework in front of a large TV and computer.