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>
Answer:
The solubility of any substance in water depends on its polarity. The polar molecule dissolves more easily in the water than the non polar molecule. Amino acids have different polarity at different pH.
(a) (Lys-Ala)3 : The (Lys-Ala)3 contain more positive charge and highly polar the at pH 7 as compared with the (Gly)20 that remains uncharged and has less polarity.
(b) (Glu)20 :This amino acids negatively charged at pH 7 and highly polar than the (Phe-Met)3 which is non polar or less polar and hence least soluble in water.
(c) (Asn-Ser-His)5 is highly polar at pH 3 as compared with the (Ala-Asp-Gly)5 that contains the carboxylate groups of Asp residues that are partially neutral. The (Asn-Ser-His)5 contains = the imidazole groups of His residues are fully polar and soluble in water.
(d) (Asn-Ser-His)5 is polar at pH 6.0 because both have polar side chains Ser but (Asn-Ser-His)5 is only partially partially protonated due to the His side chains. Thus, (Asn-Ser-His)5 is more soluble in water.
The theory is the Continental drift, the super-continent is called the Pangaea.
<span>C Glucose is broken down in a cycle of reactions to form pyruvate
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