life cycle of the frog![click to hear](/images/speaker.jpg)
The stages of development are the egg, the tadpole and the adult; each stage usually lasts several weeks, but can last up to two years in some species.
tadpole ![click to hear](/images/speaker.jpg)
Aquatic larva of the frog having a large head and a slender body ending in a tail; it breathes through gills.
forelimb ![click to hear](/images/speaker.jpg)
The forelimbs appear during the last stage of the tadpole’s metamorphosis.
hind limb ![click to hear](/images/speaker.jpg)
The hind limbs appear after the gills.
operculum ![click to hear](/images/speaker.jpg)
Thin bony plate of skin covering the gills and having a posterior valvular opening, the hearing organ.
external gills ![click to hear](/images/speaker.jpg)
Respiratory organs that filter water and take in food particles; they are later replaced by internal gills.
eggs ![click to hear](/images/speaker.jpg)
Embryonic stage of the frog resulting when the egg is fertilized by the sperm.