Question

Which is the second hardest material in the human body ?

Answer 1

Hint:Minerals make up up to 96 percent of the body's toughest component. Water and other organic components make up the rest. Hydroxyapatite, a crystalline calcium phosphate, is the main component in this material. This material has no blood vessels or nerves once fully created.

Complete answer:
Enamel on our teeth is the strongest material in the human body; keratin is softer than enamel, thus you can scratch your fingernails with your teeth, but not other areas of your body with your fingernail.
Keratin or fingernails is the second hardest material in the human body.
Keratin is a member of the scleroprotein family of fibrous structural proteins. In vertebrates, keratin is a type of keratin. Scales, hair, nails, feathers, horns, claws, hooves, calluses, and the outside layer of skin are all made of this structural substance. Keratin also helps to protect epithelial cells from harm and stress. In both water and organic solvents, keratin is very insoluble. Keratin monomers bundle into intermediate filaments, which are tough and create robust unmineralized epidermal appendages in reptiles, birds, amphibians, and mammals.
Excessive keratinization aids in the fortification of some tissues, such as bovine and rhino horns, and the osteoderm of armadillos. Chitin is the only other biological substance that may approximate the hardness of keratinized tissue. The primordial, softer forms of keratin are found in all vertebrates, while the harder, developed versions are found solely in sauropsids (reptiles and birds). Because keratin is resistant to digestion, cats regurgitate hairballs.
Although spider silk is classed as keratin, the protein's creation may have developed independently of vertebrate silk production.

Note:
The toughest material in the body is tooth enamel. Enamel develops on the tooth as it develops within the gums before erupting into the mouth. In humans and many other animals, including certain fish species, tooth enamel is one of the four primary tissues that make up the tooth.