Give examples of natural and artificial light sources.

Natural light sources: bonfire, sun, stars, firefly, moon, etc. Artificial light sources: incandescent lamp, candle, fireplace, TV screen, electric stove spiral, etc.

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.