Commentator: Many people argue that the release of chlorofluorocarbons into the atmosphere is harming humans by damaging the ozone layer, thus allowing increased amounts of ultraviolet radiation to reach Earth. βββ βββββββ βββββ βββ β βββββββββ βββββββ βββββββ βββ βββββ ββββββ ββββ ββ βββββββββββ ββββββ ββ βββ ββββββββ ββββββββββ βββββββ βββ βββββββββββ ββββββββββ βββ ββββ βββββββ ββββ βββ βββββββββ ββββββ ββ βββββββββββββββββββ ββββββ βββββ ββ ββ ββββββ ββ βββββ ββββ βββββ βββββββββ ββ βββ ββββββββββ ββββ ββββββ ββ ββββ ββββ
The commentator concludes that there is no reason to think that chlorofluorocarbons (CFCs) in the atmosphere are harming humans by damaging the ozone layer and allowing excess ultraviolet (UV) radiation to reach Earth. As support, the commentator cites a supernova 300,000 years ago that damaged the ozone layer much more than CFCs are estimated to be damaging the ozone layer today. Since our earliest ancestors were not impacted by this damage 300,000 years ago, the commentator says that humans today wonβt be harmed by the damage caused by CFCs.
The commentator assumes that humans are similar enough to βour earliest ancestorsβ to conclude that something that didnβt damage our ancestors wonβt damage us. The commentator also assumes that there have not been changes in the past 300,000 years that may augment the harm of a damaged ozone layer.
Which one of the following, ββ βββββ βββββ ββββ βββββββββ ββββββ βββ βββββββββββββ βββββββββ
Extraterrestrial influences on βββ βββββ βββββ ββββ ββ βββββ ββββ βββββ ββββ βββββββββββ βββββ
Natural events, such ββ βββ ββββββββ ββ ββββββββββ ββββββββ ββ ββββββ βββ βββββ βββββ ββββββ
Our earliest ancestors βββββββββ βββββββ βββββββββββββββ ββββββ ββββ ββββ βββββββββ ββββ ββ βββ ββ βββ βββββββ βββββββ ββ βββββββββββ ββββββββββ
The ozone layer βββββββββββ ββ β ββββ βββββ βββββββ βββββββββββββ ββββββββββ
Scientists have discovered ββββ βββββββ βββββββ ββββββββ ββ βββ βββββββββ ββββββ βββ ββββββ ββ βββββ βββ βββββββββ ββββββββ ββββββ