Put these events in the order they occurred, starting with the earliest. Benton MacKaye proposed the idea of a continuous trail through the Appalachian mountains. President Carter signed legislation to protect the land surrounding the Appalachian Trail. A five-year-old boy became the youngest person to thru-hike the Appalachian Trail. A blind man and his seeing-eye dog completed their thru-hike of the Appalachian Trail.

Below is the list in chronological order: 1. Benton MacKaye proposed the idea of a continuous trail through the Appalachian mountains.   • (This proposal was made in 1921, laying the conceptual groundwork for what would become the Appalachian Trail.) 2. President Carter signed legislation to protect the land surrounding the Appalachian Trail.   • (During his presidency in the late 1970s, actions were taken to conserve and protect the trail’s corridor.) 3. A blind man and his seeing‐eye dog completed their thru‐hike of the Appalachian Trail.   • (This inspiring feat occurred after the trail’s protection was in place, marking one of the notable milestones in its human history.) 4. A five‐year‐old boy became the youngest person to thru‐hike the Appalachian Trail.   • (This record-setting accomplishment is the most recent of the listed events.) This ordering reflects the evolution of the Appalachian Trail—from its visionary proposal, through efforts to secure its future, to the remarkable human achievements of later years.