Assertion (A) : Fishes survive in ponds even when the atmospheric temperature is below 0°C.

Reason (R) : The anomalous expansion of water helps in preserving aquatic life.

1. both A and R are true and R is the correct explanation of A
2. both A and R are true and R is not the correct explanation of A
3. assertion is false but reason is true
4. assertion is true but reason is false

both A and R are true and R is the correct explanation of A

Explanation

Assertion (A) is true because this happens in cold regions during winter, even when the air freezes, fish can survive underwater.

Reason (R) is true because of water's anomalous expansion, it is densest at 4°C, so water at 4°C stays at the bottom, while water above 4°C (and eventually ice) remains at the top. This keeps the lower layers liquid and habitable for aquatic life. Hence, the anomalous expansion of water explains why the bottom of the pond remains unfrozen, allowing fish to survive.