What effect did these innovations have on the war?
they made the war last longer than previous wars.
they made secret operations extremely important
. they led to rapid changes in the size of armies
. they resulted in higher casualty rates than in the past.

. They resulted in higher casualty rates than in the past.

Explanation:

The First World War, formerly called the Great War, was a warlike confrontation centered on Europe that began on July 28, 1914 and ended on November 11, 1918, when Germany accepted the conditions of the armistice.

After six months of negotiations at the Paris Peace Conference, on June 28, 1919 the Allied countries signed the Treaty of Versailles with Germany, and others throughout the following year with each of the defeated powers. More than nine million combatants and seven million civilians lost their lives (1% of the world's population), an extraordinary figure, given the technological and industrial sophistication of the belligerents.

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