Because of photosynthesis
The correct answer is option D, that is, ice floating on the water surface.
The cohesive forces among the molecules of a liquid are accountable for the process called surface tension. Surface tension refers to the tension of the surface film of a liquid resulting due to the attraction of the particles in the surface layer by the bulk of the liquid that seems to reduce the surface area.
The examples of surface tension are walking of small insects on water, floating of a needle, the surface tension of water offers the essential wall tension for the creation of bubbles with water, and surface tension is accountable for the shape of liquid droplets.
The low density of ice makes it float at the liquid water surface, like ice cubes in a glass of water, or an iceberg. The lower density of water in its solid form is because of the way hydrogen bonds are aligned as it freezes, the water molecules are pushed further far away in comparison to the liquid water.
