I think it is the Epidermis
<span>Epithelial tissue is densely packed cells that used most in the area where protection is needed. This cells mostly used in skin, some with more keratin which will increase their ability to protect. In bone, the main protective layer is calcium mineral which was deposited by osteocytes. Because this bone doesn't really need more epithelial cells. Bone tissue only needs a good vascularization and connective tissue to support it.
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Answer: The answer is rock.
Explanation: A rock is a a solid substance in which it is composed of large quantities of one mineral, or contains 2 or more minerals.
