Firm Tissue That Replaces Bone, Found in Ears

Puzzle 19 of Making Sushi Pack

Question is: Firm Tissue That Replaces Bone, Found in Ears

and the answer is: CARTILAGE

Word Meaning:

CARTILAGE — (anatomy, uncountable) A usually translucent and somewhat elastic, dense, nonvascular connective tissue found in various forms in the larynx and respiratory tract, in structures such as the external ear, and in the articulating surfaces of joints. It composes most of the skeleton of vertebrate embryos, being replaced by bone during ossification in the higher vertebrates.

Definitions from Wiktionary.