Bacteria are the most primitive organisms; they live everywhere. They are found in hot springs, in deep ocean basins and in ice. They were the first to appear on the planet in those days when there was no land and there was no oxygen. These bacteria were anaerobes, chemotrophs: they used the energy of chemical bonds. It was the bacteria that began to synthesize new substances (anabolism) and break down compounds (catabolism). Water provides all chemical reactions. Life originated in water, without it reactions of the metabolism of bacteria, the first living organisms, were not possible.
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.