Final answer:
The young Sioux warrior who led the attack on Capt. Fetterman in Wyoming was Crazy Horse, a key figure alongside Sitting Bull in the resistance against U.S. expansion efforts.
Step-by-step explanation:
The young Sioux warrior who led the attack upon Capt. Fetterman in Wyoming was Crazy Horse. Crazy Horse was a key figure in the resistance against the U.S. government's efforts to confine the Sioux people to reservations. Although the mentioned engagement did not involve Capt. Fetterman, it's important to note that the Battle of the Little Big Horn is more famously associated with Sitting Bull and George Armstrong Custer.
While Red Cloud did sign a treaty that ceded the Black Hills to the government, it was Sitting Bull and Crazy Horse who continued to resist through force of arms. In the battles that followed, including the infamous Battle of the Little Big Horn, the leadership and military strategies of Sitting Bull and Crazy Horse were significant in leading the Sioux to several victories. However, the eventual suppression of the Native-American insurgencies, including the tragic encounter at Wounded Knee, marked the end of armed resistance and led to further hardships for the Sioux and other tribes.