A reaction to the chemical warfare used during world war I was the use of. (a)trench warfare
(b)gas mask
(c)zeppelins
(d)infantry attacks

i believe it would be a gas mask.

Explanation:

If it has something due to with chemicals and stuff id assume the men reacted with gas masks to be able to survive the chemicals and yea i hope im right

50% because no one is smart enough to relize that money makes the world go round and 99% of the earth hates donald trump the other 1% is the republicans go figure right

chronological thinking is an indispensable tool to structure a historical narrative and to give meaning to a sequence of events. the final section presents the results of a survey to test the chronological thinking of lower secondary school students carried out by the educational research institute.