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 3
The correct answer is Option (3) → Cardiac glycosides
Plants cannot run away from herbivores, so many of them defend themselves with chemicals. Calotropis makes a poison that acts on the heart (“cardiac” means of the heart).
Option (1) Pancreatic glycosides — Incorrect. “Pancreatic” refers to the pancreas, a digestive gland of animals. The poison of Calotropis is named after the heart, not the pancreas.
Option (2) Cardiac glycoproteins — Incorrect. Glycoproteins are proteins with sugar chains attached, such as many proteins on cell surfaces. The poison of Calotropis is not a protein.
Option (3) Cardiac glycosides — Correct. These highly poisonous chemicals are a chemical defence of the plant. Cattle and goats do not browse on Calotropis because of them.
Option (4) Cardiac glycogens — Incorrect. Glycogen is the storage carbohydrate of animals, kept in the liver and muscles. It is a food reserve, not a poison.
Note: A similar question was also asked in CUET (UG) 2025 on 20-05-2025 (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.”