Explain the transmission channel shown in the figure with its characteristics and uses. Also, discuss cross-breeding of local buffalos and causes/preventive measures of heart attack. Finally, explain why organisms survive in 0°C water, the biological significance of this, and a related daily life problem.

a) Due to the anomalous expansion of water. Water is densest at $4^\circ \text{C}$, allowing the bottom layers to remain liquid and warmer, while ice forms on the surface.

b) Water at $0^\circ \text{C}$ (ice) floats at the top because ice is less dense than liquid water. When water freezes, its molecules arrange into an open, crystalline structure due to hydrogen bonding, which occupies more volume than the same mass of liquid water, thus decreasing its density.

c) The biological significance of this characteristic is that it allows aquatic life to survive in cold climates. The layer of ice that forms on the surface of lakes and ponds acts as an insulator, preventing the water below from freezing solid and maintaining a suitable temperature for fish and other aquatic organisms to live.

d) One problem caused by this property of water in daily life is the bursting of water pipes in cold weather. As water freezes inside pipes, it expands, exerting immense pressure that can cause the pipes to crack or burst.