Why was the end of the civil war the bloodiest?

The Civil War was America's bloodiest conflict. ... Nearly as many men died in captivity during the Civil War as were killed in the whole of the Vietnam War. Hundreds of thousands died of disease. Roughly 2% of the population, an estimated 620,000 men, lost their lives in the line of duty. :)

Explanation:

small european communities with shared traditions consolidated into large new states (apex)

the scientific revolution brought us a renewed understanding of humanity and our place in the universe, new scientific equipment, and new laws as a basis for future scientific discovery.