Biomagnification of DDT causes a decline in bird population by
a. Bringing disturbance in calcium metabolism
b. Thinning of eggshell
c. Premature breaking of eggs
d. All of the above

Hint: The fixation impact happens because DDT is utilized and discharged considerably more gradually than the supplements that are passed starting with one trophic level then onto the next. So, DDT collects in the bodies (particularly in fat).

Complete answer:
Dichlorodiphenyltrichloroethane or DDT is a translucent, dull, and scentless compound which is utilized as an insecticide. DDT on overflow from the fields arrives at the water bodies and gets collected in the assortments of fishes.

At the point when fishes are eaten by birds, it gets amassed in the assortment of birds, and subsequently, in this way it enters the natural pecking order. With each progressive trophic level, the convergence of DDT increases, and this is known as biomagnification.

High centralization of DDT upsets the calcium metabolism of birds and causes diminishing of eggshells and untimely breaking of eggs. This prompts a decrease in their population.

Biomagnification of DDT prompts an expansion in its fixation at the higher trophic level and its higher focus in birds prompts the unsettling influence in their calcium digestion. This causes the untimely breaking of eggs in feathered creatures because of the diminishing of eggshells. Thus, the biomagnification of DDT prompts an abatement in the bird population.

Hence, the correct answer is option (D).

Note: Dichlorodiphenyltrichloroethane, ordinarily known as DDT, is a lackluster, dull, and practically unscented glasslike synthetic aggravate an organochlorine. Initially created as an insecticide, it got notorious for its natural effects. Biomagnification of DDT prompts an expansion in its focus at the higher trophic level and its higher fixation in winged creatures prompts the unsettling influence in their calcium metabolism and untimely breaking of eggs. This prompts a decrease in their population.