Question

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> What is the anomalous expansion of water, and how does it help aquatic life?

Answer 1

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Water has an unusual property. When it is cooled from a higher temperature, it contracts to 4°C increasing its density and decreasing its volume just like any other liquid does. But on cooling further below 4°C, water starts expanding, as a result, its volume increases and density decreases till the temperature reaches 0°C at which water freezes into ice to float in liquid water.
This anomalous property of water enables aquatic plants and animals to survive in colder regions of the world because even when the water of ponds, lakes, and rivers, freezes on the top but remains as liquid below the ice layer.