1- Which of the following is not the consequence of ozone layer depletion?
a) Increased ultraviolet rays
b) Cyanobacteria are sensitive to UV radiation and would be affected by its increase.
c) Malignant melanoma-Another form of skin cancer
d) None of these

2- Who discovered the ozone layer?
a) Henri Buisson & Charles Fabry
b) Carl Sagan & Charles Fabry
c) G.M.B Dobson
d) Carl Sagan & G.M.B Dobson

3- What is the average concentration of ozone in the ozone layer of the atmosphere? (PPSC 2020)?
a) Nearly 20ppm
b) Greater than 10 ppm
c) Less than 10ppm
d) none of these

4- CFCs (chlorofluorocarbons) are greenhouse gases that have caused a rise of 3 degree C in the global temperatures in the past century. Name the CFC that is used in refrigerators.?
a) Carbon dioxide
b) Methane
c) Ammonia
d) Freon