Question

how can amphibian's brathe on water as well as on land

Answer 1

They breath in water with the help of their gills and they breath on land with help of lungs.......

Answer 2

he adult frog has lungs, like other land vertebrates.

It is also able to absorb some oxygen through its skin. But generally, frogs cannot stay indefinitely under water; they must eventally come to the surface to breathe.

Larval frogs — of course — hatch in water from shell-less eggs laid in water, like those of fish, and develop gills, like fish, for the first stages of their life. Then they grow legs, grow lungs, their tail shrinks to nothing, their gills shrink to nothing, and they become adults.

Some amphibians — such as the axolotl salamander — retain gills in their adult form. But I’m not aware of any frogs that do so.

Hope it helps!!