When flies having a gray body and normal wings were crossed with flies having a black body and vestigial wings, the f2 generation showed a phenotypic ratio of 3: 1, and not 9: 3: 3: 1.

which of the following could be a correct explanation for this ratio?

a- genes for body and wing size were on the same chromosome and inherited together
b- genes for body and wing size assort independently
c- genes for body color and wing size are inherited separately from each parent

i think the answer is

mass

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.