Question

During severe winters when lakes are frozen, fishes still survive. Why?

• A. The ice acts as an insulator and thus prevents low thermal currents to reach the bottom
• B. The bottom of the lake is not frozen
• C. The fishes can withstand very low temperatures
• D. The fishes remain in the state of hibernation

Answer 1

Answer: (B)

The bottom of the lake is not frozen

We know that the water has maximum density at $4^{0}C$. Hence during severe winters when the upper layer starts freezing , the bottom of the lake still remains in liquid form, because layers get arranged in increasing density and water at $4^{0}C$ is in liquid form. Hence, the non frozen part of lake thas is the bottom part of lake is where fishes live in severe winters.