题目:
The author refers to “bacterial infections” (see line 11) most likely in order to
选项:
A、describe the physiological function that gum performs in plants
B、demonstrate that sap is not the only substance that is transported through a plant's tissues
C、explain how modern chemical analysis has been used to clarify the function of resin
D、show that gum cannot serve as an effective defense against herbivores
E、give an example of how confusion has arisen with regard to the nature of resin
答案:
A