the eustachian tube
on land , frogs breathe with the help of lungs , and in water , with the help of gills.
Yes they do. All frogs, salamanders and Caecillians have lungs. However the tadpoles do not and develop lungs in the time that they live in water.
Gills, because lungs help it live on land.
the eustachian tube
As tadpoles they have gills and swim in the water all day, but when they become frogs they produce lungs and lungs need oxygen. So yes they do need oxygen.
backward movement of epiglotis
The epiglottis is the flap that prevents food and water from entering the trachea.
Amphibians such as toads, frogs and newts, etc.
Frogs have specialized skin that allows them to absorb oxygen from water through a process called cutaneous respiration. On land, they breathe through lungs just like mammals do, inhaling air through their nostrils and into their lungs. Additionally, when they are active, frogs can also absorb some oxygen through their mouth lining.
They have lungs. Tadpoles have gills, but lose them as they grow into frogs. Frogs can still live in water as they breathe through their skin. They also can live on land via their lungs. They are amphibious for this reason
Frogs can breathe through their skin, which allows them to breathe underwater for long periods of time. They also have lungs, allowing them to perform strenuous activities in water.