Over $10 \ ppm$ fluoride causes

Which scientist first compared the Earth's atmosphere to a greenhouse effect,and when?

Which among the following is not a greenhouse gas?

Which one of the following gases is reported to retard photosynthesis?

The depletion of ozone in the stratosphere is caused by .......

Fill in the blanks:
$(1)$ The substance that spreads pollution is called .......
$(2)$ The full form of $DDT$ is .......
$(3)$ The area from $10 \ km$ to $50 \ km$ above sea level is called .........
$(4)$ Harmful ultraviolet radiation from the sun reaching the earth is blocked by .....