(A) To help put the airplanes in order.
(B) To help forecast the weather.
(C) To grade the soldiers on their success in the military.
(D) ** To make it difficult for the enemy to know their plans.
EXPLANATIONS BELOW
Concept note-1: -In World War I and World War II, the United States military relied on a unique series of codes to keep its messages safe from the enemy. These codes weren’t based on cutting-edge technology or complex mathematical equations, though.
Concept note-2: -The Code Talkers participated in every major Marine operation in the Pacific theater, giving the Marines a critical advantage throughout the war. During the nearly month-long battle for Iwo Jima, for example, six Navajo Code Talker Marines successfully transmitted more than 800 messages without error.
Concept note-3: -Their encrypted code, which was never cracked by the enemy, helped the United States win its way across the Pacific front from 1942 to 1945. Historians argue that the Navajo Code Talkers helped expedite the end of the war and, undoubtedly, saved thousands of lives.
Concept note-4: -During World War II, sending and receiving codes without the risk of the enemy deciphering the transmission required hours of encrypting and decrypting the code. The U.S. Marine Corps, in an effort to find quicker and more secure ways to send and receive code, enlisted Navajos as code talkers.