During the Civil War, why was the North ultimately able to defeat the South?

The North was able to defeat the South due to many factors. The first factor is attrition. The North had more men serving in the armed forces than the South—at the end of the war, the North had over one million men in uniform. The North also had a greater industrial capacity to supply these men. The North had a much better infrastructure system than the South, and it could use its railroads to send men and supplies where needed. The food in the Union army was not always the best, but it was at least present under normal circumstances; many Confederate soldiers either had to forage for food or do without, especially in the latter stages of the war.
The North also had better finances. The Confederate treasury lacked the capacity to keep up with the demands of a war this size. The North, while having to implement an income tax, was never insolvent. The North also had the benefit of being recognized by major governments. The Confederacy bet their survival on being recognized by European powers who might become allies, but due to a naval blockade by the North and William Seward's war threats, Europe never came to the South's aid. Britain and France realized that they could get their cotton from North Africa and India and, thus, avoid the American situation altogether. After the Emancipation Proclamation in 1863, many Britons saw the North as being morally right. This also coincided with major Confederate defeats in the field at Gettysburg and Vicksburg, thus proving that Southern independence was not assured and that any support given would be a risk many in Europe did not wish to take.