Select the correct pairs of organism and defence: Organism Defence a)…

The correct answer is Option (4) → b and c

Prey and plants have evolved defences against those that eat them.

a) Insects and frogs — Distasteful — False. Some insects and frogs are cryptically coloured (camouflaged), so the predator cannot easily see them. Distaste is the defence of the Monarch butterfly.

b) Calotropis weed — Poisonous — True. Calotropis makes highly poisonous cardiac glycosides. That is why cattle and goats never browse on it.

c) Acacia, Cactus — Thorns — True. Thorns are the most common morphological defence of plants against herbivores.

d) Monarch butterfly — Camouflaged — False. The Monarch butterfly is highly distasteful to birds because of a chemical in its body. It gets this chemical as a caterpillar by feeding on a poisonous weed.

Only pairs b and c are correct.

NCERT Extract:
Population Interactions – “… Prey species have evolved various defenses to lessen the impact of predation. Some species of insects and frogs are cryptically-coloured (camouflaged) to avoid being detected easily by the predator. Some are poisonous and therefore avoided by the predators. The Monarch butterfly is highly distasteful to its predator (bird) because of a special chemical present in its body.”
Population Interactions – “… Thorns (Acacia, Cactus) are the most common morphological means of defence. … 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.”