Answer :
Final answer:
Scientific studies indicate that 80% of the atmospheric chlorine is human-made, largely due to the release of chlorine atoms from the decomposition of chlorofluorocarbons.So, the correct answer is C).
Explanation:
From scientific studies, it has been determined that 80% of the chlorine in the atmosphere is human-made. Chlorofluorocarbons (CFCs), once widely used as refrigerants and propellants, release chlorine atoms into the upper atmosphere. These atoms play a major role in the depletion of the ozone layer, contributing to the annual thinning over Antarctica. Chlorine has two stable isotopes, chlorine-35 and chlorine-37, with natural abundances of 75% and 25%, respectively. However, this information about natural isotopic abundances does not provide the source of atmospheric chlorine but simply their distribution in nature.
