Final answer:
Adults have 206 bones in their skeleton, with bones being categorized based on their shape and function, and some fusing over time. The axial skeleton has 80 bones, including the skull with 22 bones and the vertebral column with 26 bones. Joints where bones meet allow for varying degrees of movement and stability.
Step-by-step explanation:
Once the skeleton fuses together, adults have 206 bones in their body. These bones are categorized based on their shapes and functions. The axial skeleton includes 80 bones like the skull, vertebral column, and the thoracic cage. The skull alone is comprised of 22 bones, with the mandible being the only movable bone. The vertebral column is formed by 26 bones, including 24 vertebrae along with the sacrum and coccyx, which are fused bones. As the body matures, some bones which start as separate pieces fuse together, like certain vertebrae in the spine.
Joints are points where bones meet, and they vary in the range of movement they allow. Some joints provide high mobility, while others offer stability with little or no movement. This is crucial as the skeleton provides structural support, protects various organs, and allows a range of movements essential for daily activities.