In the conversion of wood into coal, it is first converted into a spongy material called (a)_______, then (b) __________ and finally (c) ____________.
The slow process of conversion of wood into coal over millions of years is called carbonization.
The wood converted first into a spongy material called peat, then lignite and eventually into coal (anthracite).
Concluding statement
In the conversion of wood into coal, it is first converted into a spongy material called (a)peat, then (b) lignite and finally (c) coal (anthracite).