Which organization came to dominate the Alliance movement in the 1890s?

Farmers Alliance

Explanation:

By 1880 the Grange movement began to decline, replaced by the Farmers' Alliances. By 1890 the Alliance movements had members from New York to California totaling about 1.5 million. A parallel African-American organization, the Colored Farmers National Alliance, numbered over a million members

the option which was not a function of missionaries in the northwest was the first one - they established posts for trading furs and other goods.

missionaries were sent around the world to spread religion and their knowledge and others - they were not merchants who sold furs and other goods.