What features of thermal expansion of water are important for life on Earth?

When cooled from 4 to 0 C, water does not contract, but expands and its density decreases. Therefore, in winter, less dense water cooled near the surface of lakes and seas does not sink down, and they do not freeze to the bottom.

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.