A Improvement in Researching Diseases B The Results of Plant Diseases C Mistake made in Diagnosis D Killing Insects E A Maj

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问题 A  Improvement in Researching Diseases
B  The Results of Plant Diseases
C  Mistake made in Diagnosis
D  Killing Insects
E  A Major Crop Disease
F  The Reasons of Plant Diseases
A  famines in poor countries
B  have low immunity to them
C  an increase of world population
D  improving growing conditions
E  lead to political unrest
F  attack wheat