Answer:
Underneath the frozen upper layer, the water remains in its liquid form and does not freeze. Also, oxygen is trapped beneath the layer of ice. As a result, fish and other aquatic animals find it possible to live comfortably in the frozen lakes and ponds. ... This irregular expansion of water is called anomalous expansion.
Step-by-step explanation:
so pretty much its because there is water under the top frozen layer and air is trapped underneath the ice