You must have seen the weed Calotropis growing in abandoned fields. The plant produces highly poisonous ___________ and that is why you never see any cattle or goats browsing on this plant.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Cardiac glycosides
Plants cannot run from herbivores, so many defend themselves with chemicals that make the animal sick, stop it from feeding or even kill it. Calotropis makes highly poisonous cardiac glycosides, chemicals that act on the heart. So cattle and goats do not graze on it.
Option (1) Cardiac amino acids — Incorrect. There is no such group of poisons. Amino acids are the building blocks of proteins.
Option (2) Cardiac glucose — Incorrect. Glucose is a simple sugar used for energy, not a poison.
Option (3) Cardiac glycerol — Incorrect. Glycerol is part of fats, not a plant poison.
Option (4) Cardiac glycosides — Correct. Calotropis produces highly poisonous cardiac glycosides. This chemical defence against herbivores is why cattle or goats never browse on it.
Note: A similar question was also asked in CUET (UG) 2025 on 29-05-2025 (Slot 1).
NCERT Extract:
Population Interactions – “… Many plants produce and store chemicals that make the herbivore sick when they are eaten, inhibit feeding or digestion, disrupt its reproduction or even kill it. You must have seen the weed Calotropis growing in abandoned fields. The plant produces highly poisonous cardiac glycosides and that is why you never see any cattle or goats browsing on this plant.”