They [DDT and other pesticides of its type] tend to be endlessly recycled in the food chains on which birds and animals and man himself are completely dependent.
A.The food chains for living creatures depend on the recycling of those chemicals. B.The cycle of those chemicals in the food chains for living creatures never stops. C.There is always a great influence of those chemicals on the food chains. D.No living creatures can live those chemicals in their food.正确答案B
