Ключевые слова: background, biology, boy, casual, caucasian, chemical, chemistry, child, children, class, classroom, closeup, cover, desk, discovery, education, examining, experiment, gloves, hands, indoors, kid, lab, laboratory, learning, looking, male, microscope, microscopic, person, pupil, research, school, science, scientific, sitting, slide, slip, student, study, studying, teen, teenage, teenager, test, unrecognizable, white,