Atoms of a given element will have the same mass.

Atoms of the same chemical element do not always have the same mass because, although the number of protons in the nucleus is the same for all atoms of the same element, the number of neutrons is not. Most elements as they occur naturally on earth are mixtures of several isotopes.

Explanation:

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.

a- multicellular

b-eukaryotic

c-no cell wall

d-heterotrophic

e-autotrophic