Exposure to a noise level of $............$ or more for a short period can damage the eardrums,leading to permanent hearing impairment. (in $,dB$)

Oil slick causes mass scale death of fishes due to

Which of the following statements are correct regarding Eutrophication?
$I-$ Streams entering into a lake introduce nutrients like nitrogen and phosphorus,which encourage the growth of aquatic organisms.
$II-$ As the lake's fertility increases,plant and animal life flourish.
$III-$ Organic remains begin to deposit at the bottom of the lake.
$IV-$ Organic waste materials continue to accumulate in the lake.
$V -$ The lake becomes shallower and warmer.
$VI -$ Cold-water organisms are replaced by warm-water organisms.
$VII -$ Marsh plants take root in the shallows and begin to fill in the original lake basin.

Differentiate between Brown air and Grey air.

Which one of the following pesticides is banned nowadays?

Cotton pollen grains are an important pollutant in which of the following cities?