What was the primary duty of the 10th Cavalry when it was first organized? A Proteoting nettlers from attacks by the Apache B Transporting supplies across the western territories C Training new recruits for the U.S, millitary D Guarding work orew bullding rallroads

## Step 1<br />The 10th Cavalry is one of the original "Buffalo Soldier" regiments formed after the Civil War. It was established in 1866 as part of the peacetime reorganization of the U.S. Army. The primary duty of the 10th Cavalry, like other regiments of the time, was to protect the western frontier. <br /><br />## Step 2<br />The options provided in the question suggest various roles that the 10th Cavalry might have played. However, the most accurate role based on historical records is that the 10th Cavalry was tasked with guarding work crews building railroads. <br /><br />## Step 3<br />This role was particularly important during the westward expansion of the United States, where the construction of railroads was a critical infrastructure project. The 10th Cavalry's duty was to protect these work crews from potential threats, including Native American tribes and outlaws who might have opposed the expansion.