Final answer:
Bones are in a state of constant turnover through a process called bone remodeling. Osteoclasts break down old or damaged bone, while osteoblasts create new bone to replace it, ensuring bone strength and mineral balance.
Step-by-step explanation:
Bones are always being produced, repaired, and broken down in a continuous, lifelong process called bone remodeling. This dynamic activity involves osteoclasts and osteoblasts, two types of bone cells with contrasting roles. Osteoclasts are responsible for resorbing and dissolving bone minerals, allowing for the removal of old or damaged bone, while osteoblasts lay new bone matrix to replace it. Approximately 10 percent of an adult's skeletal mass is remodeled each year to maintain bone strength, repair minor damages, and ensure mineral homeostasis in the blood.