Which of the following is $NOT$ present in photochemical smog?

Nutrient enrichment of a lake will cause

Which of the following statements is/are correct?
$I.$ Chemical fertilizers cause pollution of water bodies as well as groundwater,besides getting stored in crop plants. Therefore,environmental scientists are pressing for a switch over to organic farming.
$II.$ Organic farming is a form of agriculture that relies on techniques such as crop rotation,green manure,compost,and biological pest control.

Identify the correct statement regarding Eutrophication.

Which of the following are correctly matched?
$I.$ Arsenic poisoning $-$ Black foot disease
$II.$ Secondary effluent treatment $-$ Biological process
$III.$ Pyrolysis $-$ Solid soil waste disposal
$IV.$ Tubifex $-$ Water pollution indicator
$V.$ Biomagnification $-$ Degradable pollutants

The quantity of $CO_2$ in the atmosphere is about (in $\%$)