Option A would be incorrect. Having a protective shell on an animal’s back would be one of the ways they would be protected against predators. And having a backbone wouldn’t really make a good shield against predators.
Option B is incorrect. The pancreas regulates blood glucose, not the backbone.
Option D would also be incorrect. It doesn’t limit movement unless it’s bent or positioned abnormally. Or unless it’s broken or malfunctioned.
The only option that is correct is option C. Hope it helps. ^^
