1. The document discusses the economic similarities and differences between trade, investment, and labor migration. It presents classical economic theories that view them as substitutes, such as comparative advantage and absolute advantage theories. 2. International regulation of trade, investment, and labor migration is discussed. Trade has the most developed multilateral rules under the WTO, while investment agreements are largely bilateral. Labor migration lacks comprehensive global governance and policies mostly focus on high-skilled workers. 3. Immigration differs from trade in key ways. Economic gains differ between developed and developing nations. Countries may act unilaterally on immigration but trade requires reciprocity between partners. People do not behave like goods in terms of movement across borders.