Question

if backbone is not flexible,what would happen?

Answer 1

if backbone is not flexible then you will not be able to move freely amd this will restrict your daily activities like it will be impossible to run, sleep, bend etc. you feel feel like a paralysed patient.

Answer 2

If our spine or the backbone wasn't flexible it would be impossible to sit , bend or even sleep .It would be difficult to run as our back keeps on moving while we run.