What group replaced Knights of Labor as the largest labor organization in Texas going into the 1900s?

American Federation of Labor

Explanation:

The Knights of Labor was a national union that was particularly popular in Texas. They were known and are remembered for there reform philosophy which includes equal pay for all workers regardless of gender, child labor laws and industrial safety laws. However, they started fading away in 1886; although was officially shut down in 1917 which was after been gradually replaced by another national labor union called American Federation of Labor (AFL). AFL was founded by some unionists in 1886.

answer; andrew jackson approved nullification by signing it into law,and john calhoun opposed it saying it was unconstitutional;