__ Gas, Chemical Agent Used in the WWI Trenches
This page is the CodyCross answer for the clue below from Amusement Park, Group 218, Puzzle 5 (Water Slides).
Question is: __ Gas, Chemical Agent Used in the WWI Trenches
and the answer is: MUSTARD
Word Meaning:
MUSTARD — A plant of certain species of the genus Brassica, or of related genera (especially Sinapis alba, in the family Brassicaceae, with yellow flowers, and linear seed pods).
Definitions from Wiktionary.