Why do some vertebrates like a hellbender salamander exchang

Why do some vertebrates, like a hellbender salamander, exchange oxygen as well as carbon dioxide through their skin but bony fishes, like a goldfish, only exchange oxygen? (Choose One)

A. Goldfish do not produce CO2 since they live completely underwater

B. Goldfish have gills that diffuse CO2 while hellbender salamanders do not

C. Only young goldfish diffuse just O2 through their skin but adult goldfish diffuse both gases

D. Hellbender salamanders have hair-like projections on their skin, enabling them to diffuse both gases

Solution

Answer - Option D - Hellbender salamanders have hair like projections on their skin, enabling them to diffuse both gases.

Because they have cutaneous respiration.