Because of different kinds of waxes they use to make the different candles.
The chimicals in some liquids burn others do not.
Because larger stars burn their hydrogen faster than smaller ones.
Farming and soaping candels
There is no wood that does not burn. All types of wood are combustible and can burn if exposed to high enough temperatures. Some woods may burn more slowly or with less intensity than others, but they are all capable of burning.
bibiagraphy
Everybody studies it: some for longer than others.
Most computers now have the capability to burn a DVD. Some people illegally burn full length movies, but others burn things like home movies or free content.
well some lasers can burn and some cannot. and some that cannot are more powerful than others
The reason some bubble gum brands last longer is because of the way they are made.
Because they are stupid!
Some phases of mitosis are longer than others because different stages have different tasks or functions. Therefore depending on the task it has to do, or how complicated a phase is, one might be longer than another that has n easier job. :)
All bears have tails, Some have longer tails then others.