Which of these techniques was used extensively during world war i? trench warfare guerilla tactics aerial bombing airborne forces

Thrench warfare was used extensively during World War I. The first option is correct.

Trench warfare consists on a type of land warfare using occupied fighting lines made up largely of military trenches, in which troops are well-protected from the enemy's small arms fire and are sheltered from artillery.

The most famous use of trench warfare is the Western Front in World War I, which was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918.

may i have the answer choices?