83121
Its anatomy typifies the tendency of bird evolution on oceanic islands , with few predators and abundant food : a generally robust physique at the expense of flight abilities , resulting in reduced wing muscles and a diminished keel on the sternum .
 sternum
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:
 sternum