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DDT is an insecticide that can remain in the bodies of insects and then is trans

ID: 49974 • Letter: D

Question

DDT is an insecticide that can remain in the bodies of insects and then is transferred to the fat of the animals who eat the insects. Based on what you know about bioaccumulation, who would be most impacted by DDT?

birds who eat the insects (trophic level 2)

small mammals who eat the insects (trophic level 2)

birds of prey who eat small mammals and other birds (trophic level 3)

all are equally affected

Black-footed ferrets live in prairie dog holes once the prairie dogs have moved on from the holes. This is an example of

mutualism

commensalism

parasitism

competition

birds who eat the insects (trophic level 2)

small mammals who eat the insects (trophic level 2)

birds of prey who eat small mammals and other birds (trophic level 3)

all are equally affected

Explanation / Answer

Answer 1) Bioaccumulation refers to the accumulation of certain chemical in a living organism. All organisms are thus equally at risk. Hence correct option is (d).

Note: It is biomagnification , which affects the organisms more at higher trophic levels. In that case , organisms at highest trophic level would be at maximum risk, for example option (c) in the above question.

Answer 2) Black foot ferrets benefit from dog without causing harm to it. Thus, it shows commensalism .

Hence correct option is (b): commensalism.