Ключевые слова: analysis, analyze, analyzing, bacteria, biological, biology, biotechnology, chemical, chemistry, dirty, drinking, ecology, environment, environmental, equipment, experiment, filtration, flask, glass, hand, health, importance, lab, laboratory, lake, liquid, nature, ocean, outdoor, person, pollution, purification, purity, quality, research, researcher, resources, river, sample, science, scientific, scientist, sea, substance, test, testing, toxic, tube, water, woman,