When an object rests on a surface, such as a table, for example, the downward force it applies to the surface is counteracted by an equal but upwards force, or reaction, applied by the surface. See more at Newton's laws of motion. A response to a stimulus, such as a reflex.
State. Aquatic Invasive Species: Snakehead (PDF | 201 KB). Indiana Department of Natural Resources. Northern Snakehead. Maryland Department of Natural Resources. Northern Snakehead Fish (Channa argus). New York Department of Environmental Conservation.
An invasive species is an exotic species whose introduction into an ecosystem in which the species is not native causes or is likely to cause environmental or economic harm or harm to human health. It is important to note that when we talk about a species being invasive, we are talking about ecosystem or environmental boundaries, not political ones.