There are two types of animals: cold-blooded and warm-blooded. The first include fish, lizards, insects. They carry cold in an inactive state. The second includes birds, mammals. In the cold season, they regularly increase their body size and the weight of internal organs related to the regulation of metabolic processes (heart, kidneys, liver) and protruding parts of the body (ears, tail)
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.