Final answer:
The nucleus pulposus is the gel-like central region of an intervertebral disc that provides padding, weight-bearing, and movement between adjacent vertebrae. With age, the water content of the nucleus pulposus decreases, causing the disc to become thinner and less flexible.
Step-by-step explanation:
The nucleus pulposus is the gel-like central region of an intervertebral disc. It provides padding, weight-bearing, and movement between adjacent vertebrae. The nucleus pulposus has a high water content that serves to resist compression, making it important for weight-bearing. With aging, the water content decreases, causing the disc to become thinner and reducing flexibility and range of motion.