How gas is formed ,

as i told u earlier the full process of forming oil beneath the earth that oil is formed by the remains of living creatures in the spam of millions of years deep under the earth, for gas is the same process but oil is the first form of petroleum that produced from the organic material in a chain of longer hydrocarbons but when temperature and pressure increase then hydrocarbons get shorter and break away, then they give light oil after some further increase in temperature it hydrocarbons get more shorter and change its form into gas,