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.
Summary. Northern snakeheads (Channa argus) are a fish native to eastern Asia (Courtenay and Williams, 2004), and were recently introduced to North America. The first reproducing population was found in Crofton Pond, MD, in 2002 and was eradicated that year when Maryland DNR poisoned the pond with Rotenone.ummary. Northern snakeheads (Channa argus) are a fish native to eastern Asia (Courtenay and Williams, 2004), and were recently introduced to North America. The first reproducing population was found in Crofton Pond, MD, in 2002 and was eradicated that year when Maryland DNR poisoned the pond with Rotenone.