Final answer:
Amphibians may have lungs, gills, and use skin as a respiratory surface.
Step-by-step explanation:
Amphibians may have lungs, gills, and use skin as a respiratory surface. Young amphibians use gills to breathe, while adult amphibians develop lungs. They can also respire through their skin, which must remain moist for diffusion. On the other hand, reptiles breathe only through their lungs and do not have the ability to respire through their skin. Therefore, the correct answer is a. Amphibians.