(i) It is present only in troposphere. (ii) It is present in very small quantities in stratosphere. (iii)It can be beneficial or harmful, depending upon its location and concentration. (iv) It shields the surface of the earth from ultraviolet (UV) ...

The depletion of ozone layer is linked to synthetic chemicals such as chlorofluorocarbons (CFCs) which are used as refrigerants, aerosol sprays and in fire extinguishers.

Fuel is burned in the rocket and the exhaust gases are made to escape in a downward direction through a narrow nozzle. As a response, the rocket accelerates upward.