The two organisms which breathe only through their moist skin are :
(a) fish and frog
(b) frog and earthworm
(c) leech and earthworm
(d) fish and earthworm
Answer : (c) leech and earthworm
It is so because both have a thick supply of capillaries just under their skin's surface, moist and thin walled marked with dense capillaries for easier diffusion.