Answer:
high temperature and high pressure
Explanation:
Coal is one of the solid minerals found underground. Coal is believed to have been formed from vegetation during the carboniferous era. The decomposition of these materials under pressure in the absence of air led to the formation of coal.
In the process of carbonization, the vegetation was converted in stages to peat, lignite, bituminous coal and anthracite.
The formation of anthracite is favored by high temperature and high pressure underground.
<u>Answer:</u>
<em>Because there is not enough evidence to prove just one theory</em>
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<u>Explanation:</u>
It is tough to explain the whole development of the earth together with some different theories. We don't know how long the whole universe will last or we don't know is there a probability for the universe to get extinct.
Everything related to universe is still mysterious and every theories which has been proved till today can be modified at any time because we know that the universe is expanding and we cannot state a stable theory for its origin. However, that depends on the future which we cannot define and it also modify the possible fate of the world.
