Concept:The human vertebral column is divided into distinct regions.Each region has a fixed number of vertebrae.Explanation:The adult human vertebral column contains 33 vertebrae in total.These are grouped as follows:Cervical vertebrae: 7 in the neck.Thoracic vertebrae: 12 in the chest region.Lumbar vertebrae: 5 in the lower back.Sacral vertebrae: 5 fused to form the sacrum.Coccygeal vertebrae: 4 fused to form the coccyx, or tailbone.Adding these gives 7+12+5+5+4=33.The sacral and coccygeal vertebrae fuse during growth, but they are still counted as vertebrae.Answer:B. 33