What are the four primary elements found in coal? 90% carbon, 3% oxygen, 4% hydrogen, and 1% sulfur. What forms of air pollution do these elements become as part of coal combustion? When coal is burned for fuel, it combines with oxygen in air to form several air pollutions. What substances are contained within coal ash?
It is an oil painting on canvas.   It is to show Picasso's anger at the bombing of the little Spanish town Guernica in 1937.  .
After the bombing, Picasso was made aware of what had gone on in his country of origin. At the time, he was working on a mural for the Paris Exhibition to be held in the summer of 1937, commissioned by the Spanish Republican government. He deserted his original idea and on 1 May 1937, began on Guernica.