Is it ensure, insure, or assure?
the sound-resonating throat pouch of male frogs and toads (amphibians of the order Anura). Vocal sacs are outpocketings of the floor of the mouth, or buccal cavity. Frogs display three basic types of vocal sacs: a single median throat sac, paired throat sacs, and paired lateral sacs. (Lateral sacs are located just rearward of the angle of the jaw on each side of the head.) All three types, whether single or paired, open into the buccal cavity by paired slits. Each slit is located on either side of the base of the tongue.