Q.Name important defense mechanisms in plants against herbivores.

Step 1. The most common morphological defence in plants is the presence of thorns, seen for example in Acacia and Cactus, which physically deter herbivores from feeding. Step 2. Many plants additionally produce and store chemical defences -- secondary metabolites that make a herbivore sick if eaten, inhibit its feeding or digestion, disrupt its reproduction, or even kill it outright. Step 3. Calotropis, commonly found in abandoned fields, is a clear example: it produces highly poisonous cardiac glycosides, which is exactly why cattle and goats are never seen browsing on it. Step 4. A number of commercially important plant chemicals -- nicotine, caffeine, quinine, strychnine and opium -- are, in fact, exactly this kind …

Recall the two broad categories of anti-herbivore plant defence given in the cha …

• Naming only one category (e.g., only thorns) and omitting the equall …