An x-ray has shown spondylosis of the spine involving all levels with disk space narrowing which is most prominent at l5/s1. mri has been advised ?

That is: basically degenerative arthritis of the spine. Not sure what the question is exactly. If they are recommending an MRI, it might be because the X-ray findings do not explain your symptoms

NOT: without a specific CLINICAL reason....never just for radiologic findings (The exception is when the RADIOLOGIST suggests that MRI scanning is indicated for specific question or finding on routine films!)