Mostly air .
The paired nares are another term for the nasal openings on a pig. These nares take in air to the sinuses.
For the most part, frogs breathe air through the mouth, and utilize internal nares when doing so outside of the water. In the water, they can put just enough of the external nares above water, but this is more important to get rid of carbon dioxide, as frogs can diffuse oxygen from the water through their skin.
Nasopharnx
Internal nares allow for the passage of air from the nose to the pharynx.
Very few species of bird actually have feathers covering the nares, or external nostrils. Of these, the woodpecker's the one who needs it to filter the air, specifically from wood particles.
nares are nostrils. the maxillary bones form the lateral margins of external nares/nostrils
The external nares are the actual nostril openings of the nose. The function of the external nares is to prevent debris from entering the nasal cavities and then the lungs.
External Nares
External nares ( Nostrils) are the openings formed by the external nose that open into the nasal cavity.
external nares
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Nostril
Nares are the openings of the nasal cavity, commonly called nostrils. We have two sets of openings called anterior and posterior nares that move air through the nasal cavity into the pharynx and lungs.
external nares
The nostrils or nasal openings, -- the anterior nares being the external or proper nostrils, and the posterior nares, the openings of the nasal cavities into the mouth or pharynx.
Nares are the external openings of the nose (human, animal, or reptile). These are also known as nostrils or the nasal passages.
Respiratory system.