Which claim correctly describes how genes can produce a phenotype? one gene is responsible for all traits. each trait is determined by a single gene. one gene can be responsible for many traits. each gene is responsible for exactly one trait.

The answer is the third option. One can be responsible for many.

what school and grade?

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.