<span>ENZYMES ARE PROTEINS. All proteins are made up of amino acid.. Enzymes are used as catalysts in metabolic reactions in living organisms. They help to speed up the rate of chemical reaction but they are not used up in the reaction. Enzymes requires optimum conditions to function optimally. </span>
The answer to this is DNA.
Thanks to recycling, we barely mine lead any more. An estimated 85 percent of lead in use today goes into batteries, mostly for automobiles. And when the batteries run down, 99 percent of this lead is recycled to make new batteries.
SI units are a modern form of the metric system.