How is the burnt fuel able to leave out of the combustion chamber?

Items are similar to the free issue items, but their access is limited. (clo5) a)-bin stock items free issue b)-bin stock controlled issue c)-critical or insurance spares d)-rebuildable spares e)-consumables

What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.

Wiy doeres rere okhn a pump whon working betwon the same pressure range?