Malthus' ideas regarding supply and demand influenced Darwin because limited natural resources force individuals to with each other, and not every individual will have the opportunity to reproduce.

compete

Explanation:

Limited natural resources force individuals to compete with each other and only strong individuals are able to compete and thereby reproduce effectively.

According to Malthus, population growth has the capacity to outrun the supply of food, and hence, if humans must experience better living conditions, there should a form of population control by controlling the birth rate.

Darwin extrapolated from Malthus' idea and opined that limited natural resources will only make individuals compete with each other and in this capacity, weak individuals might not be able to effectively compete, thus, leading to weakness in reproducing.

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.