Прочитайте текст и определите какой из заголовков соответствует тексту Ultra-violet rays are familia...: ответ на тест 781302 - Английский язык

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Ultra-violet rays are familiar to most people as the particular art of sunlight that is "health-giving".
The effect of the ultra-violet rays is to produce in the skin the vitamin that is important for the promotion of bone-growth.
The use of these rays in diagnosis is a powerful weapon of medicine.
One of the most valuable uses of ultra-violet rays in industry is the testing of the quality of certain goods.