In my definition, very hot. For most people, it's very warm, but not quite hot. Room temperature is about 68. So this is on the warm side. It's typical weather of late spring, or very early fall.
When primary and secondary consumers die secondary rebuilds
Nucleic acid
Coal
solar power
If you have a list of possibilities count the carbon atoms in the formula.
Otherwise there many possibilities, if we restrict ourselves to hydrocarbons:-
hexane, C6H14
hexene C6H12, various isomers
hexyne, C6H10, various isomers
benzene, C6H6.
there are also alcohols, aldehydes ketones carbohydrates metal complexes the list is very large.
Hydroelectric
Petroleum is already a separated fossil fuel.
amino
chemical bonds
Cells grown into the correct shape
natural gas