Question

what substance reacts with acids in the dough to create carbon dioxide gas, air pockets and and a nice, flakey cookie?
sugar
oxygen
baking soda (sodium bicarbonate)
rewatch

Explanation:

Baking soda (sodium bicarbonate) is a base that reacts with acids in dough to produce carbon dioxide gas, creating air - pockets and resulting in a flaky texture. Sugar and oxygen do not have this reaction with acids in dough to produce carbon dioxide for the described baking effect.

Answer:

C. baking soda (sodium bicarbonate)