What change in u. s. immigration policy took place in 1882?

The Immigration Act of 1882 was a United States federal law signed by President Chester A. Arthur on August 3, 1882. It imposed a head tax on noncitizens of the United States who came to American ports and restricted certain classes of people from immigrating to America, including criminals, the insane, or "any person unable to take care of him or herself." The act created what is recognized as the first federal immigration bureaucracy and laid the foundation for more regulations on immigration, such as the Immigration Act of 1891.

B.) nitrogen fixationnitrogen fixation is the process of nitrogen molecules seeping into the soil and inside plant roots and bacteria. it gives more "life" to plants