250-17

250-17

There has been a 30 to 40 fold increase in the incidence of malaria caused by increasing mosquiito resistence  against pesticides.

A) Increase in the incidence of malaria caused by increasing mosquiito resistence against

B)   increase in the incidence of malaria because of increasing resistence of mosquitos to

答案是B 我想問的是A為什麼不對  謝謝