Why were so many individual killed or wounded during this World War 1?

World War I saw unprecedented levels of casualties due to a combination of factors, including the introduction of industrialized warfare, which brought about more lethal weapons like machine guns, artillery, and poison gas. Trench warfare also led to prolonged battles with devastating attrition rates, as soldiers faced horrific conditions and high mortality in confined spaces. Additionally, the war involved widespread conscription, drawing millions of soldiers into combat, and the scale of the conflict spread across multiple fronts, contributing to the staggering number of deaths and injuries.