Ключевые слова: analysis, analyzing, bacillus, bacteria, biochemistry, biological, biology, biotechnology, bottle, chemical, cholera, clarity, close, concept, danger, distribution, ecology, environment, environmental, epidemic, experiment, glove, hand, health, impurities, infection, laboratory, lake, liquid, material, measurement, nature, pollution, pond, radiation, research, river, sample, state, study, substance, swim, test, testtube, tube, utensils, waste, water, wednesday,