**Core Concept:** Cellular components of cartilage and bone tissue, including their respective matrix proteins and functions.

**Why the Correct Answer is Right:** Chondrocytes are the primary cells found in cartilage tissue. They secrete a unique extracellular matrix (ECM) composed mainly of type II collagen and aggrecan, which provide elasticity, shock absorption, and lubrication, allowing for smooth joint movement. On the other hand, bone tissue is composed of osteocytes, which are responsible for bone remodeling, mineralization, and maintenance. In bone tissue, the ECM primarily consists of collagen types I, II, and III, along with hydroxyapatite crystals, which give bone its hardness and strength.

**Why Each Wrong Option is Incorrect:**

A. Osteocytes are present in bone tissue and play a crucial role in bone remodeling and mineralization, making this wrong.
B. Chondrocytes are found in cartilage, not bone tissue, making this incorrect.
C. Aggrecan is a proteoglycan specific to cartilage ECM, not present in bone tissue.
D. Type II collagen is a component of cartilage ECM, not bone tissue, making this wrong.

**Clinical Pearl / High-Yield Fact:**

The presence of chondrocytes and their specific matrix proteins in cartilage distinguishes it from bone tissue, both in terms of cellular composition and ECM composition. This knowledge is essential for understanding normal joint function and the pathophysiology of cartilage and bone disorders such as osteoarthritis and chondrodysplasias.