Answer:Plant material, lignite, sub-bituminous, bituminous, and anthracite
Explanation: Decomposing plant material over time and under pressure forma lignite which is a very dirty type of coal. As time and pressure increase, more energy is released and the trend points that there are less pollutants when it is burned!
You need to look at the Periodic table. The atomic number is the number of protons. When you subtract the atomic number from the mass number, you get the number of neutrons. i.e. for Beryllium (Be) the atomic number is 4, so it has 3 protons. Its atomic mass about 9, so 9-4=5. Therefore, there are 5 neutrons.
Answer:
c I've taken chem 3 times
Explanation: