The statement which best explains why Pepsin will not break down starch is that enzymes only work for specific substrates.
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What is an Enzyme?</h3>
This is referred to as a biological catalyst which helps to speed the rate of chemical reaction in the body by lowering the activation energy needed to start it up. it is also proteinous and can be denatured by heat and other substance such as chemicals.
They are also substrate specific which means they can't act on any type of substance. For example enzyme such as amylase acts on only starch while pepsin acts on only protein.
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<span>Nuc is short for nucleus</span>
Some isotopes, however, decay slowly, and several of these are used as geologic clocks. Dating rocks by these radioactive timekeepers is simple in theory, but the laboratory procedures are complex. <span>All methods rely on the fact that certain elements (particularly uranium and potassium) contain a number of different isotopes whose half-life is exactly known and therefore the relative concentrations of these isotopes within a rock or mineral can measure the age.</span>