In living organisms, the ratio of the naturally occurring isotopes of carbon, C-12 to C-13 to C-14 is fairly consistent. When an organism such as a woolly mammoth died, it stopped taking in carbon, and the amount of C-14 present in the mammoth began to decrease. For example, one fossil of a woolly mammoth is found to have 1/32 of the amount of C-14 found in living organisms. Identify the type of nuclear reaction that caused the amount of C-14 in the woolly mammoth to decrease after the organism died.