U. S Government posters during World War II often displayed: -slanted language
-ethnic biases
-nationalistic biases
-all of these choices are correct

All of these choices are correct. US Government posters during World War II often displayed slanted language, ethnic biases and nationalistic biases.

Explanation:

The posters placed by the federal government on public roads, transportation and other places of high circulation of people during World War II had as their main and fundamental objective the creation of a united and strong domestic front, where all citizens collaborated with the effort of the thousands and thousands of Americans on the battlefront through the production of food, medicine, supplies, and weapons, and the rationing of their own consumption in order to allocate most of the resources to these soldiers. In addition, these posters attempted to encourage many young Americans to join the ranks of the military, by spreading nationalist (such as Uncle Sam and his "I Want You" message) and ethnicists slogans (such as posters depicting Japanese and Germans as sadistic and evil beings).

All this propaganda was effective in its initial purposes, since it generated a feeling of union and collaboration that allowed a greater allocation of resources for the armed forces that were fighting in Europe and the Pacific.