Ultraviolet rays with a wavelength of more than 0.3 microns make up 10% of the radiant energy reaching the earth’s surface. In small doses, they are necessary for animals and humans. Under their influence, vitamin D is formed in the body. Insects visually distinguish ultraviolet rays and use this to orient themselves on terrain in cloudy weather.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.