Why can amphibians live in land and water?
They can extract oxygen from the atmosphere in their environment through their skin and also have gills.
Amphibians are not necessarily able to survive on land and in water at the same time. During the amphibian life cycle, they might have gills during one stage and not have gills during another. Some might always have gills and be water-bound throughout their entire lives, while others might be able to go back and forth between gills and gill-free as needed.