What isn't said about the case with PCBs?A.An accumulation of PCBs in the human body is th
What isn't said about the case with PCBs?
A.An accumulation of PCBs in the human body is the direct reason of the cancer and other severe disorders.
B.PCBs can't be disintegrated using conventional waste-treatment ways.
C.PCBs are degraded by natural processes very slowly.
D.PCBs have been found in high contents in the fatty tissues of fish.