Wood.
thay used yak dung for their fire
Fertilizer, mostly. Some people in other countries use cow or bison dung as fuel for their fires.
range fires vs. underground seam fires.
Oxygen
They used logs, hay, and other easily flammable things.
You do not use water to extinguish fuel fires. Water will only spread it.
Turf, wood and coal are 3 of the main fuels used in open fires in houses. For other types of fires, like in machinery and industry, oil or gas can be used.
Peat is a fuel that is used in some countries. It is very commonly used in Ireland, where it is known as turf. People use it for fires in their homes and some power stations use it as a fuel to generate electricity.
The Mongols primarily used animal dung, particularly from horses and cattle, as fuel for their fires. This was a practical choice given their nomadic lifestyle, as dung was readily available and easy to transport. Additionally, they sometimes used wood when available, but in the vast steppes, dung was the most common and efficient fuel source.
Not fresh out of the body but it is if allowed to dry out. People living on the Great Plains used to use cow dung to fuel fires.
Methane gas is highly flammable which makes it a good fuel source for gas burning.
Fuel to make fires.