Give reasons:

Aquatic plants and animals survive in very cold regions.

Water shows anomalous expansion. As the temperature falls below 4°C, water at the surface becomes lighter and finally freezes at 0°C to form ice, which floats. This ice layer is a poor conductor of heat, so it acts like an insulating blanket and prevents the water below from freezing. Therefore, the lower layers remain liquid and aquatic plants and animals can survive in very cold regions.