Why did robert e lee chose to fight for the confederates instead of for lincoln?

This i do not know sadly but i did some research for you and google says and i quote

"When Virginia declared its secession from the Union in April 1861, Lee chose to follow his home state, despite his desire for the country to remain intact and an offer of a senior Union command. During the first year of the Civil War, Lee served as a senior military adviser to Confederate President Jefferson Davis".

world war i began in 1914, after the assassination of archduke franz ferdinand, and lasted until 1918. during the conflict, germany, austria-hungary, bulgaria and the ottoman empire (the central powers) fought against great britain, france, russia, italy, romania, japan and the united states (the allied powers). to new military technologies and the horrors of trench warfare, world war i saw unprecedented levels of carnage and destruction. by the time the war was over and the allied powers claimed victory, more than 16 million people—soldiers and civilians alike—were dead.

explanation: