One method for separating polypeptides utilizes their different solubilities. The solubility of large polypeptides in water depends upon the relative polarity of their R groups, particularly the number of ionized groups. The more ionized groups there are, the more soluble the polypeptide. Which of each pair of the polypeptides that follow is more soluble at the indicated pH? a. (Phe-Met)3 or (Glu)m at pH 7.0
b. (Lys-Ala)3 or(Gly)m at pH 7.0
c. (Ala-Ser-Gly)5 or (Asn-Ser-His)5 at pH 6.0
d. (Ala-Asp-Gly)5 or (Asn-Ser-His)5 at pH 3.0:

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).

bcde is the incorrect answer it is a