Final answer:
Domestic commerce is the buying and selling of goods and services within a country, distinct from international trade. It can be influenced by national trade policies like import quotas and tariffs to protect domestic industries.
Step-by-step explanation:
Domestic commerce refers to the buying and selling of products within a particular country. It contrasts with international trade, which involves the exchange of goods and services across national borders. An example of trade policy at the national level is the United States imposing import quotas on sugar to protect domestic sugar producers from the threat of lower prices due to imports. The United States Department of Commerce and the United States International Trade Commission are agencies involved in monitoring and responding to trade issues that affect domestic industries, such as import dumping and unfair pricing that can be offset by tariffs.