97454
Phylogenetic analysis of available fish , tetrapod , and bird HIF-α and - β sequences shows that the isoforms of both subunits present in mammals are also represented in fish Within fish , HIF sequences group close together and are distinct from tetrapod and bird sequences .
 tetrapod, bird
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 tetrapod, bird