Match List I with List II

	List I		List II
A	Nitrogen oxides in air	I	Eutrophication
B	Methane in air	II	pH of rain water becomes 5.6
C	Carbon dioxide	III	Global warming
D	Phosphate fertilisers in water	IV	Acid rain

Choose the correct answer from the options given below :

Reason: Nitrogen oxides ($$NO_x$$) dissolve in cloud moisture and react with oxygen to form nitric acid ($$HNO_3$$), lowering the precipitation pH drastically below normal limits and causing Acid rain.

Reason: Methane ($$CH_4$$) is a potent greenhouse gas that traps infrared radiation in the atmosphere, significantly contributing to the greenhouse effect and Global warming.

Reason: Normal, unpolluted rain is naturally slightly acidic because atmospheric carbon dioxide ($$CO_2$$) dissolves in it to form weak carbonic acid ($$H_2CO_3$$), bringing the baseline clean rainwater pH to exactly 5.6.

Reason: Runoff containing agricultural phosphate fertilizers acts as a massive nutrient boost in water bodies, triggering dense algal blooms. When these plants die, their decomposition starves the water of oxygen, causing aquatic life to suffocate—a process called Eutrophication.