The hardest constituent of the tooth is A. Enamel B. Dentine C. Bone D. Pulp
Hint: The internal structure of the tooth comprises root (hidden in the gums) and crown (visible part of the tooth). The root binds the tooth as well as allows the entry of blood and nerve supply into the tooth to maintain its viability. The crown is the surface that allows the breakdown of food, as opposing teeth come together while chewing. The crown and root consist of hard and soft tissue.
Complete solution Option A. Enamel: It is the hardest, white coloured outer part of the tooth, which covers the crown of the tooth. It is mainly made up of calcium phosphate, a rock-hard mineral. Option A is correct. Option B. Dentine: The next layer down below both the enamel and cementum are dentin, the major part of the tooth. It is regarded as a hard tissue, but it is much more permeable than either of the other hard tissues to let nutrients be transferred through the layers of the tooth. Option B is not correct. Option C. Bone: The root of the tooth is inserted in bone, which is enveloped in tissue known as gingiva. The root is held on to its position by strands of tissue that arise from the nearby bone and embedded into cementum. These strands of tissue are referred to as periodontal ligaments. Option C is not correct. Option D. Pulp: The next layer below dentin is the pulp tissue, which is enclosed in the pulp cavity. The pulp cavity is provided with a rich supply of blood and nerve, which is required for maintaining tooth health. Option D is not correct.
Hence, Option A is the correct answer
Note: The glossy, white enamel that envelopes the teeth is even stronger than bone. This strong surface is composed of \[96\] percent mineral, the maximum percentage of any tissue found in the body. Thus, making it long-lasting and damage-resistant.