Can you help with the following assumptions based on trade policies, organizations, and agreements? Please be precise and answer organized.

1. Discuss how countries promote free trade and, in turn, protect the local economy from foreign investment. When presenting your answer, explain the concepts: tariffs, trade barriers, import subsidy and quota, free trade policies, protectionism, trade deficit and surplus.
2. Explain how the World Trade Organization (WTO) promotes the global integration of companies and countries.
3. Please mention and describe the regional trade agreements of the European Union, USMCA, Mercosur, ASEAN-APEC-TPP). In your answer you must include the countries that these bring together and what each agreement consists of.
4. In your own words, explain how knowledge of trade theories and policies helps to understand the environment and develop strategies to meet global challenges.