What type of nozzle is typically used for bottom placement or deep-water injection?

The correct answer, small holes drilled into galvanized pipe, is commonly used for bottom placement or deep-water injection because it allows for effective and controlled distribution of liquids in aquatic environments. This method facilitates the precise application of treatments directly to the bottom substrate or deeper areas of a body of water, ensuring that the active ingredients reach their target zone efficiently.

With this approach, the small holes in the pipe minimize disturbance of the water column above and enable the substance to permeate into sediment or plant material, making it particularly useful for targeting aquatic pests that may be present at these depths.

The other nozzle types, such as flat fan nozzles, hollow cone nozzles, and full cone nozzles, are designed for different spraying techniques where coverage of surface areas is prioritized rather than penetrating deeper into the water. These options focus on creating a broad spray pattern or a concentrated stream to manage specific surface-level applications, which is why they are not the best choice for deep-water injection.