1. This Ozone part contains the gas known as .............. .

oxygen gas

ozone gas

oxide gas

methane

2. This layer is located at the ............... of the stratosphere.

upper

middle

bottom

above

3. They discovered this layer in .............. .

1958

1908

1982

1988

4. By ultraviolet light, ............... gas is converted to ozone gas.

methane

oxygen

carbon

nitrogen

5. This Ozone hole appears above the Antarctic on ................ of each year.

eighth and ninth

fifth and fourth

first and second

third and fourth

6. This Ozone hole disappears in ............... .

December

November

October

May