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Question
Assertion :Heavy metals and persistent pesticides pass into the food chain and increase in amount per unit weight of the organism at successive trophic levels Reason: Heavy metals and persistent pesticides can be easily metabolised by the organism's body.
Assertion :Heavy metals and persistent pesticides pass into the food chain and increase in amount per unit weight of the organism at successive trophic levels Reason: Heavy metals and persistent pesticides can be easily metabolised by the organism's body.
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Solution
The correct option is C Assertion is correct but Reason is incorrect
Heavy metals and persistent pesticides (e.g., organo-chlorine or
chlorinated hydrocarbons like DDT) pass into food chain and increase in
amount per unit weight of organisms with the rise in trophic level due
to their accumulation in fat. The phenomenon is called
biomagnification/bioconcentration/biological amplification. In other
words, biomagnification refers to increase in concentration of the
toxicant at successive trophic levels. This happens because a toxic
substance accumulated by an organism cannot be metabolised or excreted,
and is thus passed on to the next higher trophic level. this phenomenon
is well-known for mercury and DDT. High concentration of DDT disturb
calcium metabolism in birds, which causes thinning of egg shell and
their premature breaking, eventually causing decline in bird population.
These chlorinated hydrocarbons affect CNS, cause softening of brain,
cerebral haemorrhage, liver cirrhosis, hypertension and also affect an
organism's reproductive system.So, the correct answer is 'Assertion is correct but Reason is incorrect'.
Heavy metals and persistent pesticides (e.g., organo-chlorine or
chlorinated hydrocarbons like DDT) pass into food chain and increase in
amount per unit weight of organisms with the rise in trophic level due
to their accumulation in fat. The phenomenon is called
biomagnification/bioconcentration/biological amplification. In other
words, biomagnification refers to increase in concentration of the
toxicant at successive trophic levels. This happens because a toxic
substance accumulated by an organism cannot be metabolised or excreted,
and is thus passed on to the next higher trophic level. this phenomenon
is well-known for mercury and DDT. High concentration of DDT disturb
calcium metabolism in birds, which causes thinning of egg shell and
their premature breaking, eventually causing decline in bird population.
These chlorinated hydrocarbons affect CNS, cause softening of brain,
cerebral haemorrhage, liver cirrhosis, hypertension and also affect an
organism's reproductive system.
So, the correct answer is 'Assertion is correct but Reason is incorrect'.
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