15. You must take an umbrella. Otherwise you will get wet. 16. If you don't work hard, you won't pass the examination.
17 We should receive enough rain. Otherwise, there will be a shortage of electricity.
18. Gopal has to consult a good doctor. Otherwise his condition may get worse.
19. They have to come early. Otherwise they won't get the tickets.​

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

Compare and contrast region e in the illustration above with region d. describe the physical characteristics of each region.

In which situations is the principle of cross-cutting relationship useful in determining relative age?