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.
In October 2002 they were added to the list of injurious species by the US Fish and Wildlife Service, which prevented the transporting of snakeheads between states and banned the importation of all twenty eight species into the USA. It is illegal to possess snakehead fish in thirteen states, but not in Maryland, the District of Columbia or Virginia. It is, however, an offence to release foreign species of fish into Marylandâs waterways.