What does the red line identify? the colorado river the oregon trail the platte river the santa fe trail

The red line identifies the Oregon Trail.

Explanation:

The Oregon Trail is a more than 3400 km long route that crosses the United States from Missouri to the mouth of the Columbia River on the Washington-Oregon border. The route was mainly used in the 19th century by pioneers who wanted to build a new life in the 'wild west' of the US in Oregon, where fertile farmland was available.

The route had several starting points in present-day Iowa, Missouri or Nebraska, but all these approach routes converged along the lower reaches of the Platte River near Fort Kearny. The eastern part of the Oregon Trail was also used by other routes to the west, such as the California Trail (from 1843-44), the Mormon Trail (from 1847) and the Bozeman Trail (from 1863). These routes split off halfway to their respective destinations. When the Transcontinental Railroad was completed in 1869, the Oregon Trail declined in significance although it was still used until the end of the 19th century. Nowadays, motorways follow largely the same route that the pioneers have followed.

Elizabeth Cady Stanton