Question

How does anomalous expansion of water help aquatic life?

• A. Water below $4^{\circ }C$ comes up to the surface because of lower density
• B. Water above $4^{\circ }C$ comes up to the surface because of lower density
• C. Water below $0^{\circ }C$ comes up to the surface because of lower density
• D. None of the above

Answer 1

The correct option is A Water below $4^{\circ }C$ comes up to the surface because of lower density

Answer is A

The anomalous expansion of water helps preserve aquatic life during very cold weather. When temperature falls, the top layer of water in a pond contracts, becomes denser and sinks to the bottom. A circulation is thus set up until the entire water in the pond reaches its maximum density at 4°C. If the temperature falls further, the top layer expands and remains on the top till it freezes. Thus even though the upper layer are frozen the water near the bottom is at 4°C and the fishes etc. can survive in it easily.