<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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The outermost layer of the pleural membrane is the parietal pleura
Answer:
I would say We don't have enough evidence or Cell theory is still changing.
Explanation:
There are so many cells in everything so it's almost impossible to know exactly what is going on. Theories about cells have been going on for over 500 years, and we still don't know exactly what is what.
Be there is different germs
