Question

\take hydrogen. add oxygen. burn.\ these instructions, which lead to an explosion at one point, are the recipe for what?
water
soil
food
breathable air

Explanation:

Hydrogen (\(H_2\)) reacts with oxygen (\(O_2\)) when burned. The chemical reaction is \(2H_2 + O_2\xrightarrow{\text{burn}}2H_2O\). Water (\(H_2O\)) is formed from hydrogen and oxygen. Soil is a mixture of minerals, organic matter, etc. Food has complex compositions like carbohydrates, proteins. Breathable air mainly contains \(N_2\), \(O_2\) etc. and not formed by just burning \(H_2\) and \(O_2\).

Answer:

A. Water