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.
Native to parts of Asia, the northern snakehead (Channa argus) was first introduced through the live food fish trade. It has taken hold in the Potomac River and its tributaries throughout Maryland and Virginia. Reasons Snakeheads Are a Threat. 1. Theyâre voracious predators and can severely alter the feeding habits, food availability, and behaviors of other members of an ecosystem. 2. They can survive in water with very low oxygen, which other fish species often cannot do. 3.