Magnetism is a class of physical phenomena that are mediated by magnetic fields. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments.The Earth's magnetic field is somewhat caused by the composition of the earth's core which is rich in iron minerals. There is a solid inner core that is made of iron which makes up to 2/3 of the moon's size. The charged metal of the iron produces electric currents, consequently resulting to Earth's magnetic field.
<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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