**Core Concept**
Bone remodelling is a continuous process involving the coordinated action of osteoclasts and osteoblasts to maintain bone health and density. It involves the resorption of old bone tissue by osteoclasts followed by the deposition of new bone tissue by osteoblasts.

**Why the Correct Answer is Right**
Bone remodelling is a tightly regulated process, and its imbalance can lead to various bone disorders. The process involves the activation of osteoclasts by RANKL (Receptor Activator of Nuclear factor Kappa-B Ligand) and its receptor RANK on osteoclast precursors, leading to the degradation of bone matrix. Osteoblasts, on the other hand, are activated by the Wnt/β-catenin signalling pathway, leading to the deposition of new bone matrix.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it contradicts the established understanding of bone remodelling. While it is true that osteoclasts resorb bone, the process is tightly regulated and involves a complex interplay of hormones and growth factors.
**Option B:** This option is incorrect because it is not a recognized aspect of bone remodelling. The process is primarily driven by the actions of osteoclasts and osteoblasts, rather than other cell types.
**Option C:** This option is incorrect because it is not a characteristic of bone remodelling. While bone turnover is an ongoing process, it is not a passive process that occurs without regulation.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that an imbalance in bone remodelling can lead to various bone disorders, such as osteoporosis or osteopetrosis, highlighting the importance of maintaining a delicate balance between bone resorption and deposition.

**Correct Answer:** D.