Personification is giving human traits to nonhuman things or organism.
In this case, the feathers are personified as being able to "dance", when obviously it isn't exactly "dancing".
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It's...almost December actually...
Answer: Her physical illness.
Explanation: Her chronic back pain troubled her throughout the years, and it only worsened later in her life, no matter how she tried with doctors. Her physical illness was the root of this cause.
