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.
Background. The northern snakehead fish (Channa argus) has been identified as an invasive aquatic fish across the country. Snakehead fish got their name because of their long, cylindrical body plan and large scales on their head that give them a snake-like appearance.
Please do not release the fish if you think that it may be a snakehead. Snakeheads have been added to the U.S. Fish and Wildlife Service's injurious wildlife list (Current Injurious Wildlife Species List ). Under this regulation, the importation into the United States and transportation across state lines are illegal .