Answer:
A Change in climate.
Explanation:
"Snowy" or better yet Arctic animals survive better in colder climates, So if their home gets warmer they will move towards colder weather. But if you want another example they will also leave if there is little to no food.
The center portion of each intervertebral disc is a filled with a gel-like elastic substance. Together with the annulus fibrosis, the nucleus pulposus transmits stress and weight from vertebra to vertebra.
