Choose the correct statement regarding the process of biomagnification of DDT in an aquatic food chain as described by the figure given below.

I. Biomagnification refers to increase in concentration of the toxicant at successive trophic levels.

II. High concentrations of DDT disturb calcium metabolism in birds, which cause thinning of eggshell and their premature breaking.

III. River water may have a very low concentration of DDT, but the carnivorous fish in that river maycontain high concentration of DDT, which is still suitable for consumption by human beings.

Which of the statements given above are correct?