Final answer:
option d,The chemical known as bone cement is Polymethylmethacrylate, which is used to anchor implants during medical procedures, unlike hydroxyapatite, which naturally hardens bones.
Step-by-step explanation:
The chemical referred to as bone cement is d) Polymethylmethacrylate. Bone contains a small number of cells embedded in a matrix of collagen fibers, which provide a surface for inorganic salt crystals to adhere. These salts, primarily hydroxyapatite, a mineral formed from calcium phosphate, combine with other inorganic salts like magnesium hydroxide, fluoride, and sulfate. The process of these salts crystallizing on the collagen fibers and hardening the tissue is known as calcification. While hydroxyapatite gives bones their hardness and strength, polymethylmethacrylate is the substance commonly known as bone cement, which is used in medical procedures such as joint replacements to anchor artificial implants.
Polymethylmethacrylate, also known as bone cement, is the correct answer to your question. Bone cement is used in orthopedic procedures to help secure implants, such as artificial joint replacements, to the bone.