Which statement best describes fluridone?

Fluridone is a systemic herbicide that inhibits the biosynthesis of carotenoids in plants, particularly target species like submersed aquatic plants. The action of fluridone is characterized by its slow-acting nature, which allows for more thorough absorption and translocation within the plant's tissues over time. This slow approach contributes to effective weed control, especially in aquatic environments, as it reduces the likelihood of sudden die-offs that can negatively impact water quality or other non-target species.

While other options mention characteristics that do not align with fluridone's behavior, such as being inactivated quickly or functioning as a contact herbicide, the essence of fluridone's mode of action emphasizes its gradual impact over days to weeks, making it capable of providing sustained control. The herbicide's effectiveness is largely due to its persistence in the environment, allowing it to be absorbed by aquatic plants at a steady pace, reinforcing the appropriateness of the chosen statement regarding its slow-killing behavior.