Question

Match the items in column $I$ and column $II$ and choose the correct option :

Column $I$	Column $II$
$A.$ UV	$i.$ Biomagnification
$B.$ Biodegradable organic matter	$ii.$ Eutrophication
$C.$ DDT	$iii.$ Snow blindness
$D.$ Phosphates	$iv.$ BOD

The correct match is:

Answer 1

UV- Snow blindness :

• Snow blindness is a temporary eye pain caused by too much exposure to UV-B rays.

Biodegradable organic matter- BOD :

• Biochemical oxygen demand (BOD) refers to the amount of oxygen consumed by bacteria and other microorganisms during the decomposition of organic matter under aerobic conditions.
• Biochemical oxygen demand (BOD) is the amount of oxygen consumed in one litre of water by microorganisms while they oxidise the organic matter at a specific temperature.
• BOD is used to measure the amount of organic matter present in the water sample.

DDT- Biomagnification :

• Biomagnification is the increase in the accumulation of toxic substances within organisms at each successive level of the food chain due to decreased excretion and metabolism. Biomagnification is caused by insecticides like dichloro diphenyl trichloroethane (DDT) and heavy metals like mercury.

Fig: Biomagnification due to DDT

Phosphates- Eutrophication :

• Eutrophication is a process in which the water bodies get enriched with dissolved nutrients like nitrogen and phosphorus that results in the excessive growth of algae(algal bloom).
• Aquatic plants die as sunlight is not able to reach them due to algal bloom.

Final answer : $A-iii,B-iv,C-i,D-ii$

Summary :

Column $I$	Column $II$
$A.$ UV	$iii.$ Snow blindness
$B.$ Biodegradable Organic matter	$iv.$ BOD
$C.$ DDT	$i.$ Biomagnification
$D.$ Phosphates	$ii.$ Eutrophication