This stated the us would prevent european nations from interfering with independent american countries. the us also agreed to remain neutral in wars between european nations.

The answer is the Monroe Doctrine. This Doctrine was stated by the fifth President of the United States, James Monroe, on December 2, 1823, and became the foreign policy of the nation for many years.  

The doctrine stated that:

● The efforts of European nations to colonize land in North or South America, are considered as acts of aggression, requiring U.S. intervention.

● Any interference by European nations with states of North or South America would also be perceived as acts of aggression and would call for U.S. intervention.

● The United States would not interfere with existing European colonies.

● The United States would not get involved with the internal affairs of European nations.

b. major john c. frémont led a rebellion called the bear flag revolt.

explanation:

during the bear flag revolt, from june to july 1846, a small group of american settlers in california rebelled against the mexican government and proclaimed california an independent republic. the republic was short-lived because soon after the bear flag was raised, the u.s. military began occupying california, which went on to join the union in 1850. the bear flag became the official state flag in 1911.