$UV$ radiation from the sun causes which of the following eye disorders?

$A$: $A$ few toxic substances often present in industrial waste waters undergo biological magnification.
$R$: $A$ toxic substance can easily be metabolised or excreted by an organism.

In Arcata,the integrated wastewater treatment was developed by creating a series of $6$ connected marshes. Its function is $............$

Which of the following human activities is responsible for desertification?

The shell of an egg in birds becomes thin (not properly formed) due to the pollution of pesticides. This occurs due to disturbed:

The $Chipko$ movement started from $........$.