The frogs are the amphibian organisms, which are capable of survival both in water as well as land. In frogs external fertilization is used as a mode of sexual reproduction. The females lay their eggs in water in the same time the males also secrete their sperms in the water. The eggs are fertilized by the sperms in water. For reproduction the frogs are dependent on water. But with the evolution of frogs, which allows them to fertilize the eggs on the land. The frogs can live away from water.
A protein channel is a transport protein that helps larger molecules, that would otherwise not be able to diffuse through the membrane of a cell to move in or out of the cell depending on the concentration gradient.
