vertebral column is made up of 33 small bones. why?

Vertebral column ,  also called  spinal column,  spine , or  backbone, in vertebrate animals, The 33 bones make up  the flexible column extending from  neck  to tail.. The major function of the vertebral column is protection of the spinal cord; it also provides stiffening for the body and attachment for the pectoral and pelvic girdles and many muscles. In humans an additional function is to transmit body weight in walking and standing...The vertebral column of human beings is the formation of four curves- cervical, thoracic, lumbar and sacral.All of these 4 curves have different functions which helps to bend and strech.