Find the odd one out.

Assertion: All birds,except the ones like koel (cuckoo),build nests for retiring and taking rest during night time (day time for nocturnal).
Reason: Koel lays its eggs in the nests of tailor bird.

Which pair represents a group of hermaphrodite animals?

Flame cells and nephridia are found in $ \text{Platyhelminthes} $ and $ \text{Annelida} $ respectively.

Which of the following organisms possess the power of regeneration?

Which feature is common among leech,cockroach,and scorpion?