1 Coal is a flammable black or brown organic sedimentary rock. Itâs mostly carbon and is typically found as layers (coal beds) or veins (coal seams).  Natural gas is a combustible mix of hydrocarbon gases. Itâs colourless and consists mainly of methane (CH4).
Anemia Anemia, a lack of red blood cells, can cause fatigue, pale skin, weakness, dizziness, headache and more. Mononucleosis Mononucleosis is a viral infection causing extreme fatigue, sore throat, fever, rash, muscle aches, and more.
Extreme fatigue: 1  99 causes: Extreme fatigue. 2  Introduction: Extreme fatigue. 3  Extreme fatigue: Add a 4th symptom. 4  Extreme fatigue: Remove a symptom.