Nuclear power plants create pollution. a. thermal pollution and heavy metals b. thermal pollution and organic materials c. radioactivity and thermal d. radioactivity and pathogens

Why are small quantities of chlorofluorocarbons so harmful to the ozone layer? a. the chlorofluorocarbons act like ultraviolet radiation causing large amount of ozone to be produced. b. the chlorine from the chlorofluorocarbons reacts with free molecules of oxygen causing a stop in ozone production c. free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone. d. chlorofluorocarbons absorb ultraviolet radiation, preventing the formation of ozone select the best answer from the choices provided

Cells tend to have a relatively small and uniform size. why aren’t cells larger?

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important