61030
The neck appears in some of the earliest of tetrapod fossils , and the functionality provided has led to its being retained in all land vertebrates as well as marine-adapted tetrapods such as turtles , seals , and penguins .
 tetrapod
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