As a biocontrol agents, the ladybird and dragonflies are useful to get rid of -
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Aphids and mosquitoes, respectively
Biocontrol uses living organisms to control pests. The ladybird beetle eats aphids, and dragonflies eat mosquitoes; the word ‘respectively’ fixes the order.
Option (1) Wasp and cockroach, respectively — Incorrect. NCERT does not use these two against wasps or cockroaches.
Option (2) Housefly and ants, respectively — Incorrect. Neither pest is what NCERT links with ladybirds and dragonflies.
Option (3) Mosquitoes and aphids, respectively — Incorrect. The right pests in the wrong order: the ladybird eats aphids, not mosquitoes.
Option (4) Aphids and mosquitoes, respectively — Correct. In biological control, natural predators are used against pests. The ladybird controls aphids, and dragonflies get rid of mosquitoes.
NCERT Extract:
Microbes as Biocontrol Agents – …
