Question

The two organisms which breathe only through their moist skin are

Answer 1

Respiration in leech

The gas exchange in case of leeches occurs through their body surface. They do not have any specific organ to carry out respiration.

Respiration in earthworm

Earthworms has cutaneous respiration i.e., they respire through their moist skin. They do not have any specific organ to carry out respiration.

Final answer
(D) Leech and earthworm