Which type of plant floats on or beneath the surface of the water?

The type of plant that floats on or beneath the surface of the water is classified as a free-floating plant. These plants are not anchored to the substrate and can move freely on the water's surface. They derive their nutrients directly from the water, and their structure is specifically adapted to allow for buoyancy, making them capable of floating. Common examples of free-floating plants include duckweed and water hyacinth, which can cover the surface of a water body.

The other options refer to different types of aquatic plants. Floating-leaved plants, for instance, have leaves that float on the surface while their roots are anchored in the sediment. Emergent plants grow from the substrate and are only partially submerged, often having their stems and leaves above the water surface. Rooted plants typically grow with their roots anchored in sediment and stems extending upwards, not floating on the water's surface.