What discovery by the Chinese led to the development of steel?

In ancient China is Qiwu Huaiwen of the Northern Wei Dynasty

Explanation:

The first famous metallurgist in ancient China is Qiwu Huaiwen of the Northern Wei Dynasty (386－557 AD), who invented the process of using wrought iron and cast iron to make steel.

abraham lincoln  (february 12, 1809  – april 15, 1865) was an american statesman, politician, and lawyer who served as the 16th  president of the united states  from 1861 until  his assassination  in april 1865. lincoln led the nation through the  american civil war, its bloodiest war and its greatest moral, constitutional, and political crisis.[2][3]  he preserved the  union,  abolished slavery, strengthened the  federal government, and modernized  the u.s. economy.

map scale refers to the relationship (or ratio) between distance on a map and the corresponding distance on the ground. for example, on a 1: 100000 scale map, 1cm on the map equals 1km on the ground.