Which of the following plants' predominance is enhanced by drawdown?

Drawdown refers to the reduction of water levels, which can create a more favorable environment for certain aquatic plant species that thrive in shallower, fluctuating water conditions. Naiads are known to thrive in these conditions, as they are often found in areas where water levels have dropped, exposing the substrate for germination and growth. Their growth is promoted by periods of reduced water, leading to greater importance in areas that experience seasonal fluctuations in water levels.

The other plant species listed, such as leafy pondweed, water smartweed, and Richardson's pondweed, typically prefer more stable aquatic environments and are not as well adapted to the conditions created by drawdown. These plants may still be present in areas impacted by drawdown, but they do not benefit from such conditions in the same way that naiads do. Drawdown allows naiads to establish and dominate in disturbed or shallow areas, reinforcing their prevalence in those environments.