1) Rotting food is caused by rotting bacteria.
2) To prevent decay, it is necessary to slow down the growth of bacteria on food. For this purpose, heat treatment of products is carried out. High temperature (during boiling, sterilization, pasteurization) kills bacteria. Low temperatures (when frozen) slow down their reproduction. Drying food prevents bacteria from easily assimilating the nutrients found there.
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.