Hey :)
a. The Silk Road was about 4,000 miles (more than 6,400 km)
b. The Silk Road earned its name from Chinese silk, which was transported along the trade networks
c. People started to use the Silk Road
when the Han Dynasty in China officially opened trade with the West in 130 B.C, the Silk Road routes remained in use until 1453 A.D, when the Ottoman Empire boycotted trade with China and closed them.
Hope this helps :)