You would want to make sure that you have controlled the variables properly, and if you determine that you did then you would repeat the experiment to be sure of the results.
Reduction is the process by which eletrons are gained by an atom.
Carbon -13 has 7 neutrons and carbon -12 has six neutrons. Carbon -12 is the most common isotope of Carbon. Carbon -14 is radioactive and vary rare. The symbols for the isotopes of Carbon atoms shown here indicate they each have six protons but mass numbers of 14, 13, and 12. Hope this helps. :)
