Ключевые слова: a zerotolerance, blackboard, bullying, chalk, chalkboard, chemistry, class, concept, educate, education, elements, furnaces, green, harassment, images, instruct, learn, nobody, noone, objects, periodic, periodic elements, picture, pictures, policy, punishment, royalty free photo, rules, school, sexual, sexual harassment, stock image, stock photograph, stock photographs, stock photos, study, table, teach, text, tolerance, train, word, zero, zero tolerance,