The pad of fibrocartilage between vertebrae that acts as a cushion is called the disk.

The answer is; intervertebral discs

This disc is composed of cartilaginous and fibrous tissue. They act as good shock absorbers and also allow individual vertebrae some degree of movement for the flexibility of the spine. The intervertebral discs also act as ligaments that hold the vertebral discs together.

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pesticide

a physical change is being made.