A plant that has stems or leaves that grow entirely below the surface of the water is known as what?

A plant that has stems or leaves that grow entirely below the surface of the water is referred to as a submergent plant. Submergent plants are adapted to live fully submerged in aquatic environments and play crucial roles in ecosystem stability. They provide habitat and food for aquatic organisms, contribute to oxygen production through photosynthesis, and help in sediment stabilization.

In contrast, emergent plants are those whose stems grow above the water level, often found in wetlands. Rooted plants typically refer to those that are anchored to the substrate, which can include both emergent and submerged species; however, this label does not specify their growth habit. Floating plants, on the other hand, have leaves and stems that float on the surface of the water, with roots that may hang down into the water but do not grow underneath. Therefore, the unique characteristic of submergent plants being completely underwater is what makes this term the most accurate description in the context provided.