Explain at least two ideas involving the history of evolutionary principles BEFORE Darwin's theory of discovery of natural selection.

Species are fixed and Earth itself is less than 10,000 years old.

Explanation:

One theory states that species are fixed, or permanent on the earth and no change occurs. The second theory was that Earth itself is less than 10,000 years old and no change occurs in it. These two ideas present before Darwin's theory of discovery of natural selection which is rejected after Darwin's theory because Darwin's theory is based on evidences.

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.