The american continents are henceforth not to be considered as subjects for future colonization by any european powers. the quotation above expresses the main idea of

The idea presented in this excerpt is that the European nations must not colonize nations in the Western Hemisphere. In return, the United States promised to keep out of the affairs of the European nations.

Explanation:

I took the test

answer: the ocean

explanation: if you map out 30 n and 40 n latitude, you will get the ocean

social contract theory, nearly as old as philosophy itself, is the view that persons' moral and/or political obligations are dependent upon a contract or agreement among them to form the society in which they live