1.what do many scientists believe contributed to the extinction of the dinosaurs
a. asteroid impact b. global warming c. predators d. plate tectonics

2.which of the following may lead to the breakdown of the ozone layer in the stratosphere a. carbon dioxide b. methane c. oxygen d. chlorofluorocarbons

3. which of the following statements about the greenhouse effect is true
a. all greenhouse gases are harmful b. life on earth is suffering because of the greenhouse effect c. life on earth would not exist without the greenhouse effect d. the greenhouse effect is caused by human activity

How do cfcs cause ozone depletion? how do cfcs cause ozone depletion? ultraviolet radiation breaks down cfcs, molecules containing chlorine. chlorine then breaks one oxygen atom away from ozone, leaving behind a paired oxygen molecule. ultraviolet radiation breaks down cfcs, molecules containing chlorine. chlorine then breaks two oxygen atoms away from ozone, leaving behind a paired oxygen molecule. ultraviolet radiation creates cfcs, molecules containing chlorine. chlorine then breaks two oxygen atoms away from ozone, leaving behind a paired oxygen molecule. ultraviolet radiation creates cfcs, molecules containing chlorine. chlorine then breaks one oxygen atom away from ozone, leaving behind a paired oxygen molecule.