Which of the following connective tissues is unique for its high concentration of proteoglycans and collagen type I in the extracellular matrix?

The connective tissue that is unique for its high concentration of proteoglycans and collagen type I in the extracellular matrix is cartilage, particularly hyaline cartilage.

Explanation:

1. Proteoglycans: These molecules consist of a core protein and glycosaminoglycan (GAG) chains, contributing to the resilience and compressive strength of cartilage.
2. Collagen Type I: While cartilage predominantly contains collagen type II, the presence of collagen type I is found in the surrounding perichondrium and in some specialized regions of cartilage, indicating a structural role and contributing to the tissue’s overall integrity.

Hyaline cartilage is particularly crucial as it provides support with some flexibility and is found in areas such as the nose, trachea, and at the ends of long bones. The combination of proteoglycans and collagen grants it a unique structure and function within the body.