Answer:
Highly valuable, courageous, critical role
Step-by-step explanation:
The given excerpt is the following:
In World War I and World War II, American Indian soldiers played a critical role in the US military effort by using their native languages as the basis for creating successful codes. The most famous of these soldiers were a group of four hundred men known as the Navajo code talkers. These innovative and courageous soldiers developed for the United States Marine Corps a virtually unbreakable military code, which proved highly valuable against the Japanese during the Second World War.
The words used to create a tone of admiration, that express respect and approval, in it are highly valuable, courageous, and critical role.
The code of the Navajo is described as highly valuable, which means that it was approved of and considered to be an important asset by the United States.
The Navajo soldiers are described as courageous, which is another positive, respected trait. They were brave and not afraid to get hurt or even lose their lives for the sake of victory.
The fact that these soldiers played a critical role means that they played a huge part in war and greatly contributed to its positive outcome.