Answer:
There are different structural adaptations that can help the organism survive in environment changes.
When the heat turns to cold a bear will hibernate. It's genetics allow the bear to keep itself warm (and of course the area that it hides itself in).
A bird will fly to a new area, where it's still hot.
Other animals, such as wolves will stop shedding and grow thicker and longer fur. This fur will help it stay warm in the winter.
All organisms have their system and each one is unique to the creature.
Hope this helped! ;)