Mammalian pinna is supported by

The correct option is "elastic cartilage".

To understand why this is the correct answer, let's break down the anatomical structure of the mammalian pinna and the different types of cartilages involved:

1. What is the Pinna?
The pinna (or auricle) is the visible, outer part of the ear in mammals. Its primary function is to collect sound waves and direct them into the outer auditory canal. To perform this function effectively, it needs to be flexible, stretchable, yet capable of maintaining its shape and structure.

2. Understanding Elastic Cartilage:
Elastic cartilage is a specialized type of connective tissue. Unlike other cartilages, its extracellular matrix is rich in networks of elastic fibers (composed of the protein elastin) along with collagen fibers. This dense network of elastic fibers gives the tissue remarkable flexibility, elasticity, and resilience, allowing it to bend easily and spring back immediately to its original shape without losing structural integrity.

3. Why other options are incorrect:
• Hyaline cartilage: This is the most common type of cartilage (found in the trachea, larynx, and ends of ribs). While it is strong, it lacks the high density of elastic fibers needed for the extreme flexibility of the outer ear.
• White fibrous connective tissue: This tissue is rich in collagen fibers, making it very strong but with minimal elasticity (found in tendons and ligaments), rendering it unsuitable for the flexible structure of the pinna.
• Calcified cartilage: This is a modified, hardened form of cartilage containing calcium salt deposits (similar to bone), which is rigid and completely lacks flexibility.

Therefore, the mammalian pinna is supported specifically by elastic cartilage to provide both structural support and the flexibility required for its function.