13. Warren is developing a model for tracking carbon atoms within an ecosystem and its environment. Warren knows that plants perform both photosynthesis and cellular respiration. Does the number of plants in the ecosystem change the effect of the ecosystem on carbon dioxide levels in the atmosphere?

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

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.

i thinking chemical change