Was anti-immigrant sentiment based largely on fears of economic competition or simply racism?

Post two 500-word essays answering these two questions: 1) Which source, the recollections, the photographs, the newspaper articles, or the manuscript census, is most useful for understanding the nature of immigrant life? Which type of primary source tells us the most about immigrants? 2) Was anti-immigrant sentiment based largely on fears of economic competition or simply racism? Put another way: What was the root fear behind the anti-immigration movement?