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.
What Are Invasive Species? Invasive species, such as feral swine, stilt grass and the emerald ash borer, damage forests, grasslands, marshes and farmlands. They may also cause harm to humans. Invasive species are non-native weeds, insect pests and other organisms introduced intentionally or accidentally by people who move them from their native range.