Organs often have a combination of pipes with one and two closed ends. For a pipe of fixed length, will the first harmonic of the pipe with one closed end achieve a higher or lower pitch than the first harmonic of a pipe with two closed ends?

in most common fires, oxygen is needed for an oxidation reaction to takes place. the combination of oxygen with any element as fuel can create fire and combustion will occur especially if wood, light materials and other combustible things are combine with oxygen.