What helped to make the First World War such a long and deadly war? large land areas that troops had to travel over

spy satellites and wireless communication

inventions like the airplane and the machine gun

alliances between Spain, the United States, and Canada

Inventions like the airplane and machine gun

Explanation:

World War I was so deadly because all of the new weapons that were invented. New technology that was being invented such as machine guns and mustard gas made war deadlier than every war before.

the following best describes postwar era writers in their works:

many writers,authors,novelists,poets concentrated more on social art and social writing and stayed away from political writings.