Answer:
Functions of epithelial cells include secretion, selective absorption, protection, transcellular transport, and sensing. Epithelial layers contain no blood vessels, so they must receive nourishment via diffusion of substances from the underlying connective tissue, through the basement membrane
Plasmid or vector transformation is the process by which exogenous DNA is transferred into the host cell. Transformation usually implies uptake of DNA into bacterial, yeast or plant cells, while transfection is a term usually reserved for mammalian cells.
h2o is water and c2o is carbon dioxide :)
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