What is the primary function of herbicides?

Herbicides are specifically designed to target and manage unwanted plants or weeds. Their primary function is to kill plants or severely disrupt their growth, which is crucial in various applications such as agriculture and pest control in aquatic environments. By employing herbicides, users can effectively reduce competition for resources between desirable and undesirable plant species, thereby preserving crop yields or maintaining the ecological balance in aquatic ecosystems.

The other options do not accurately reflect the primary intent of herbicides. Enhancing plant growth and fertilizing are functions associated with fertilizers rather than herbicides. Promoting water quality is an objective of environmentally friendly practices and management strategies but not a direct function of herbicides themselves. Thus, the role of herbicides is fundamentally tied to controlling plant life rather than promoting or enhancing it.