A nucleus. Hope this helps.
The answer is a. and b.
Diamond is pure carbon(C). Salt is pure sodium chloride (NaCl). Ocean water can contain a number of different elements mostly Water (H2O) and sodium (Na)
They are the same in that most of the reproductive organs of both sexes develop from similar embryonic tissue, meaning they are homologous. Both systems have gonads (male have testes and female have ovaries) that produce gametes (testes produce sperm and ovaries produce egg or ovum) and sex organs.
Okay, biology isn't exactly my strongest subject (it never has been), but I'm pretty sure the answer is nucleotides. DNA is made up of nucleotides. Each nucleotide contains a phosphate group, a sugar group, and a nitrogen base. There are four different nitrogen bases: adenine (A), thymine (T), guanine (G), and cytosine (C). A always pairs with T, and G always pairs with C.