What is the benefit of having discs that are tougher on the outside and jelly like on the inside?

The advantage is that these discs serve as shock absorbers, alleviating the impacts that the spine could suffer.

Explanation:

The spine or backbone is the central axis of the body responsible for sustaining our biped position. It also constitutes an important communication axis between the central and peripheral nervous system, through the spinal cord, contained in the spinal cord canal.

The spine is also formed by soft tissues such as muscles, ligaments, capsules, tendons and discs, these structures being responsible for the flexibility of the spine.

The discs specifically lie between the vertebrae of the spine. They are tough on the outside, but soft on the inside. This is a great advantage because, because of the flexibility of their interior, the discs act as shock absorbers, reducing the impact the spine suffers when moving. Thus, the discs prevent possible vertebral pain and wear.

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