**Question:** High water content is seen in which zone of articular cartilage?

**Core Concept:** Articular cartilage is a smooth, gelatinous tissue that covers the ends of bones at joints, reducing friction and absorbing shock. It is divided into three zones based on cellular composition and water content: the superficial, intermediate, and deep zones.

**Why the Correct Answer is Right:** The correct answer, zone C (hyaline cartilage), is the deepest zone of articular cartilage, which contains dense, tightly packed chondrocytes (cartilage cells). This zone has the highest water content among the three zones due to the presence of large amounts of ground substance, primarily composed of water and proteoglycans. The high water content helps maintain the cartilage's viscoelastic properties, allowing it to absorb shock and reduce friction between joints.

**Why Each Wrong Option is Incorrect:**
A. Intermediate zone (zone B): This zone has a moderate water content and intermediate cellular density, making it less suitable for explaining the high water content in articular cartilage.
B. Superficial zone (zone A): This zone has a lower water content and cell density compared to zone C, making it an incorrect choice.
D. Hyaline cartilage: Although hyaline cartilage is a type of articular cartilage, zone C represents the deepest zone and has the highest water content, making it the correct choice.

**Clinical Pearl:** The high water content in zone C plays a crucial role in maintaining the viscoelastic properties of articular cartilage, ensuring joint stability, and reducing friction and wear during movement. Understanding these properties is essential for understanding joint health and diseases like osteoarthritis, which can result from cartilage degeneration and loss of its viscoelastic properties.

**Correct Answer:** C. Hyaline cartilage