Pick the odd-one-out from each of the groups given below on the basis of respiratory organs. Give reason for your answer.

(a) cockroach, grasshopper, snail, ant

(b) lizard, cow, earthworm, snake

(c) crocodile, whale, dolphin, fish

(d) snake, tadpole, crow, goat

a) SNAIL.

The other animals mentioned above like cockroach, grasshopper and ant are insects and respire through trachea while snail being a molluscan has different organ of respiration.

b) EARTHWORM.

The rest of the animals like lizard, cow and snake respire through lungs whereas only earthworm respire through moist skin.

c) FISH.

All the other animals like crocodile, whale and dolphin have lungs as their respiratory organs but only fish respire through gills.

d) TADPOLE.

It is the odd one as tadpoles respire through gills and do not have lungs while all other mentioned animals have lungs.