Fill in the Blanks :

$(1)$ The substance that spreading pollution is called .......

$(2)$ The fullform $DDT$ is .......

$(3)$ The area of $10\, km$ to $50\, km$ from the sea level is called .........

$(4)$ Harmful ultraviolet sun radiation come to the earth is blocked by ..... 

Mention the harmful effect of ultra violet radiations. 

How can domestic waste be used as manure ? 

What would have happened if the greenhouse gases were totally missing in the earth's atmosphere? Discuss.

The possibility of photochemical smog formation will be minimum at

How does the ozone gas become ?