Question

How did vertebrae prevent from grinding against one another

Answer 1

they prevent grinding by thin fleshy cartilageous tissues......

Answer 2

In vertebra there are several columns which sits together on each other to form he spinal cord. Between each column there is a vertebral disc which prevents 'vertebrae' from 'grinding' against one another.

Explanation:

A vertebra or a 'spinal cord' is made up of 24 different vertebrae which ranges from neck to the upper hips. Each vertebra contains a disc which acts as a 'shock absorber' and prevents them from grinding with each other. The discs are made up of fibrous shell in which there is a gel like filling which acts as a lubricant.