Practice question

Condition possessing two separate external nostrils or nares connected via internal choanae to buccal cavity is termed dirhinous derived from Greek di two and rhinos nose, representing standard gnathostome vertebrate arrangement including fishes, amphibians, reptiles, birds and mammals where paired olfactory sacs sample water or air bilaterally improving gradient detection. Monorhinous or monorhiny describes single median nostril in cyclostomes lamprey and hagfish, trirhinous hypothetical anomaly, polyrhinous multiple irregular openings pathological not evolutionary term. Dirhiny facilitates bilateral olfaction and respiratory flushing through nasal passages.