Question

Which among the following is likely to have the highest levels of DDT deposition in its body?
A. Sea gull
B. Phytoplankton
C. Eel
D. Crab

Answer 1

Hint:
DDT is a complex chemical compound that stands for Dichlorodiphenyltrichloroethane. It is used to control the spread of malaria or as an insecticide. It is sprinkled over small grasslands or crops or in certain areas to control the spread of mosquitoes or pests that might damage the crops.

Complete step by step answer:
DDT is used as insecticide to control the spread of malaria or other diseases causing mosquitoes. It is supplied in free air or particular regions of land or to water bodies which also leads to their consumption by organisms.

DDT is showered over the crops or grasslands to control pests and mosquitoes growth and spread and to increase crop production. Due to this step, it enters into the water bodies due to run off and organisms feeding on those waters also indirectly consume DDT.

DDT gets transferred from one level to another level in the food chain. This process is called bioaccumulation. And it is said to be in highest concentrations at higher levels. This is called biomagnification.

Among all the organisms given, sea gull is a carnivorous bird that feeds on fishes which also comes in the food chain at higher levels so seagulls will have the highest levels of DDT in their bodies.

So, the correct answer is A, Sea Gull.

DDT is usually transferred from one trophic level to another per unit weight of the organism.

Note:
DDT enters the food chain through insects, plants or infected water. It accumulates in the tissues of the higher organisms who consume the lower organisms and this process is called bioaccumulation. Bioaccumulation leads to high amounts of DDT present in organisms who are present in higher trophic levels.