What is coal composed of?

Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements; chiefly hydrogen, sulfur, oxygen, and nitrogen. Hope this helps.

coal contains Carbon, hydrogen sulfur, oxygen and nitrogen.

Explanation:

We use it as a fuel in power plants.industrial furnaces.domestic cooking etc.

It is mostly used in huge boilers to make steam and used for electrical power generation

answer; i believe the correct answer is (anemia);

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.