I think I only know one & that is Temperature.
Hope I helped! ( Smiles )
The appropriate response is biochemistry. Eduard Buchner showed that aging can be achieved utilizing dead chemicals as opposed to living yeast. He built up that biochemical responses are conceivable outside living cells. He was awarded a Nobel Prize in the year 1907 for his discovery on fermentation.
Voltage sources are uses to sustain the flow of protons chemical reactions resistance in the movement of electric charge.
