Question

Bone is mainly composed of
A. Iron and phosphorus
B. Sulphur and calcium
C. Calcium and phosphorus
D. Calcium and magnesium.

Answer 1

Hint: In the vertebrates, the skeleton forms the internal framework of the body and it is made up of a strong and rigid organ known as the bones. The internal structure helps to support the body, aid in movements and protects the various organs of the body.

Complete answer:
Bones are the hard and rigid structures that form the internal skeleton of the body. It includes complex internal and external structures. Bones are made up of hard tissues which are a kind of hard dense connective tissues. The innermost portion of the bones consists of a honeycomb like structures and this arrangement provides a distinct rigidity.
The bone tissues are also known as osseous tissue and it is made up of bone cells such as the osteoblasts and osteocytes. These cells are involved in the formation and mineralization of bones. The osteoblasts form a layer of cells present on the surface of the bones which provides protection.
The matrix of the bone is made up of elastic collagen fibres. These fibres are also called ossein. The elastic collagen fibres form about 90 to 95% of the bone matrix while the remainder part is known as the ground substances.
The matrix is formed as a hard structure caused by the binding of the calcium phosphate as the inorganic mineral salts. The arrangement of calcium and phosphate in the bones occurs in the form of calcium hydroxylapatite. Hydroxylapatite is a naturally present mineral form of the compound calcium apatite. It is the mineral that provides rigidity to the bones through the process of bone mineralization.
Thus, the right option is C.

Additional information :-
The bone mineral is the inorganic part of the bone. It is formed through carbonated hydroxyapatite. It is formed from the globular and plate-like structures which are found in association of collagen fibrils. The bone fibers and salts together make the extracellular matrix of the bone tissues.

Note: Bones are made up of minerals which are inorganic part of the structure. They are hard rigid structures and are made up of minerals such as calcium and phosphate. The inorganic minerals appear in the form of hydroxyapatite. Bones form the hard and supporting framework of the body.