The word "which" in line 13 refers to A. barriers

Từ "which" trong dòng 13 đềcập đến

A. rào cản                   B. mô                          C. chất                         D. côn trùng

Dẫn chứng: If the physical barriers of the plant are breached, then preformed chemicals may inhibit or killthe intruder, and plant tissues contain a diverse array of toxic or potentially toxic substances, such as resins, tannins, glycosides, and alkaloids, many of which are highly effective deterrents to insects that feed on plants.

Chọn đáp án là C