This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Which of the following statement is TRUE about osteoblasts and chondroblasts? 
Select and explain. 
A. Terminally differentiated cells, B. In contact with neighboring cells gap junctions, C. Found in lacunae, D. Derived from mesenchymal stem cells
D: Derived from mesenchymal stem cells
Answer: D: Derived from mesenchymal stem cells 
Explanation: Osteoblasts are modified fibroblasts. Their early development from the mesenchyme is the same as that of fibroblasts, with extensive growth factor regulation. Normal osteoblasts are able to lay down type 1 collagen and form new bone. A chondroblast is a cell which originates from a mesenchymal stem cell and forms chondrocytes, commonly known as cailage cells. Chondroblasts that become embedded in the matrix are called chondrocytes. Also Know: Osteoclasts erode and absorb previously formed bone. They become attached to bone integrins in a membrane extension called the sealing zone. Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 21. Hormonal Control of Calcium & Phosphate Metabolism & the Physiology of Bone. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.