Read the paragraph from the text. By the end of the war, 421 Navajo code talkers had been trained. They
were all essential to the war effort. A number of them continued to work
with U. S. forces after the war. They had given the marines their only
unbreakable battlefield code and saved thousands of American lives. The
United States owes the Navajo code talkers much gratitude.
Which points from the paragraph are the author's opinions? Explain why they
are opinions rather than facts.