Step 1: Concept
Mineralization of hard tissues in the body requires specific inorganic elements.
Step 2: Meaning
Bone and tooth enamel are primarily composed of hydroxyapatite crystals.
Step 3: Analysis
Hydroxyapatite is formed from calcium and phosphorus. While both are needed for both structures, they are the fundamental building blocks for the skeletal and dental systems.
Step 4: Conclusion
Calcium and phosphorous are the essential minerals for bone and teeth health.
Final Answer: (A)