While I wouldn't really want to store any of those next to a heat source, it is the aerosol can that is likely to explode.
If a rock is hot, it has been heated by a source of heat, either man-made or natural. However the rock itself, may be the source of heat - in which case it contains radioactive material undergoing decay and is most likely dangerous!
The sun
The most major heat source of the body is the blood cells in our body, however it can be our muscles as well.
Thunderstorms are most likely to form during warm weather. In simple terms, the heat is their source of energy.
Some Bias
most likely, it's coal
most likely, it's coal
EM (or emergency heat) can be used if you have a problem with your other heat source such as a heat pump. In most cases, you will not need this but what it does is bi-passes the primary heat source and allows your secondary heat source (normally your furnace) to become the primary.
Anything flammable or more likely anything that is in a compressed cylinder in liquid or gas form. E.G. Nail polish, air freshener, gasoline.
Well it depends what heat you are refering to. One source is the sun, the other source is gas - which can be used as a heating source.
heat