Cells can contain thousands of different genes; however, there is often only a small percentage of these genes that are being expressed at any given time. This indicates that: a
gene expression is a controlled process
b
unused genes are removed from the marshmallow
c
the expression of genes is random
d
cells are unable to express all genes

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.