What are the morphological and chemical defence of plants against phytophagous insect?

Explanation

1. Thorns in acacia and cactus.
2. Store chemicals that make them sick when they are eaten, inhibit feeding or digestion, disrupts its reproduction or even kill.
Weed calotropis: They produce highly poisounous cardiac glycosides. Nicotine, caffeine, quinine, strychnine, opium are the other chemicals, which produce plant defence agianst grazers and browsers.