Which of the following statements about DDT are false? I. DDT stands for dichloro-diphenyl-trichloropropane and is an organochlorine insecticide. II. DDT is soluble in water but insoluble in organic solvents. III. High concentrations of DDT disturb calcium metabolism in birds, which causes thinning of eggshell and their premature breaking. IV. In fish-eating birds, the DDT can ultimately reach a very high level of 25 ppm.