What makes the matrix of bones hard in the human body?

The matrix of bones in the human body is hard due to the presence of calcium salts. This makes bones strong enough to support the weight of the body and protect delicate organs. Cartilages in the Skeletal system are specialised connective tissues that have a slightly pliable matrix due to chondroitin salts. This makes them ideal for joints where bones need to move smoothly against each other.The Skeletal system is grouped into two main divisions - the axial skeleton which includes the bones that make up the central axis of the body such as the skull, spinal column, rib cage and the appendicular skeleton which includes bones of the upper and lower limbs and the bones that attach the limbs to the axial skeleton. Bones play a crucial role in supporting and providing structure to the human body. They also protect delicate organs, store minerals, and produce blood cells.