The thing that brought an end to the bear flag republic was: The arrival of US Troops in California.
The bear flag republic was founded by several hundreds of immigrants in California that rebelled against the Mexican department Government because they're not allowed to buy land in the state.
The soviet invasion of Afghanistan
The invasion also ended a period of lessened tension between Moscow and Nixon administration. The period known as detente,had seen an increasing easing of tensions and threats of nuclear war between the two cold war proteges before the soviet decided to invade the country.
Answer:
American Robert Gray’s most important accomplishment was claiming the Columbia River of the United States.
George Washington is the answer
The answer to this question is B