Persons confined to bed are less likely to develop sores on their bodies if they use a water bed rather than an ordinary mattress. Explain.

Bed sores are developed on the body when the skin and the corresponding tissue that lies below it get damaged due to cut off circulation of blood.
The proportion of water is evenly distributed in the waterbed. When people are confined on the waterbed, they experience evenly distribution of pressure on their back. Due to this uniform pressure, the parts of the body in contact with the waterbed cut off the circulation of blood. This damaged the tissue and the skin and developed sores.
But when people are confined on the ordinary mattress, there is no evenly distribution of pressure over the surface of the body contact with the water bed. This makes blood to flow in the tissue and skin. Thus, it is less likely to get damaged.
Therefore, people lying on the ordinary bed are less likely to developed sores on their bodies.