Aconfounding variable can also be considered an extraneous variable. true or false?

Yes it is true that a confounding variable can also be considered an extraneous variable.

An extraneous variable can also be a confounding variable. An extraneous variable clarifies the relationship between the independent and dependent variables. A compounding variable influences both the dependent variable and independent variables.

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.