The bark of a tree is impervious to gases and water because bark cells are dead cells of the epidermis and compactly arranged without intercellular spaces. They contain a chemical called suberin in their walls that make them impervious to gases and water and it doesn't allow gases or water into the tree as bark cells are in the bark outer most layer of the tree.
The effects of electrical stimulation on the sciatic nerve may be observed by watching the nerve under a dissecting microscope. Electric stimulation therapy is a therapeutic treatment that applies electrical stimulation in treating muscles spasm and pain. An assortment of lower back problems can cause the pain that radiates along the sciatic nerve.
Any theory that the structure of the solar system in which earth is assumed to the centre of it all.
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