Though some bacteria cause disease and illness in humans, the majority are harmless. Some bacteria are used to aid digestion, used in preparation of certain foods, used to battle infections or used by industry. Bacteria have many important roles in nature. All but one is a role of bacteria out in the world around us.

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i havent taken the psat, but i have the sat, make sure to bring some snacks, because youre in there forever, 2 sharp number two pencils, an sat approved calculator, and maybe a jacket.   your phone and any books will be taken up, so don't try to bring them(but they will be given back at the end of the testing).   good luck!   i hope you do well!

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for this

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