Answer:
F Anthracite (the hardest coal)
Explanation:
Coal is a sedimentary rock that is formed from plant materials. These plant materials must have been trapped and compacted in an environment where they are not able decay. Such an environment is a swamp.
The first grade of coal that forms initially in such an environment is called PEAT. Peat is soft coal that still contains some plant materials. It has a high moisture content and the amount of carbon is still quite low.
With increasing pressure and compaction, PEAT grades into LIGNITE which has more carbon atoms in it. Lignite is more combustible although it is quite soft too. Lignite grades into SUB-BITUMINOUS coal and then BITUMIOUS coal.
The highest grade of coal is ANTHRACITE which is a hard coal. It has very little moisture content and rich carbon percentage in it. Anthracite yields more energy compared to other forms of coal. Anthracite is basically coal that forms at the greastest pressure. Beyond this pressure, a metamorphic transformation occurs and the coals changes to graphite.
Based on increasing pressure:
PEAT< LIGNITE< BITUMINOUS COAL < ANTHRACITE
When visiting a cave, it is important not to take any formations in the cave because : C) They took thousands of years to form, and should be left so others can enjoy them too. <span>Cavers care about the preservation of these beautiful caves and embrace the motto which they even revised to be cavern friendly :</span><span> “Take nothing but pictures, kill nothing but time, and leave nothing – not even footprints.”</span>
Chanel I think I'm sorry if it's wrong it might be mouth
Answer:
To calculate the anomalies, from each monthly data point you subtract that month’s average. These monthly averages, called the “climatology”, are shown in the top row of Figure 2.
