During world war 1 native americans were noted for which of these contributions to the war effort combat service in the army employment in war industries contributions to the medical corps use as code-breakers for the military

"Use as code-breakers for the military"

Explanation:

Key Speaker is the term used to refer to people who communicate using encrypted languages. It is usually used to name Native Americans who served in the United States Marine Corps and whose main occupation was to transmit secret military messages.

These messages were transmitted, usually by telephone or radio, using codes built on their own languages, known to small groups, sometimes dozens of people around the world, which was a great strategic advantage. This advantage lies in the fact that military codes can be broken or deciphered with relative ease, whereas such a minority human language requires a long process of study in order to understand it.

The name Locutores de claves is strongly associated with Navajo Indians, who used their language to send secret military messages during the First World War and the Second World War, serving as a great help to the US Army, mainly in the Pacific area.

the answer to your question is:

strong-mayor system

america