Wood ashWood ash is the powdery residue remaining after the combustion of wood, such as burning wood in a fireplace, bonfire, or an industrial power plant. It is largely composed of calcium compounds along with other non-combustible trace elements present in the wood. It has been used for many purposes throughout history. A comprehensive set of analyses of wood ash composition from many tree species has been carried out by Emil Wolff, among others.
Cleaner fishCleaner fish are fish that show a specialist feeding strategy by providing a service to other species, referred to as clients, by removing dead skin, ectoparasites, and infected tissue from the surface or gill chambers. This example of cleaning symbiosis represents mutualism and cooperation behaviour, an ecological interaction that benefits both parties involved. However, the cleaner fish may consume mucus or tissue, thus creating a form of parasitism called cheating.
2,4-Dichlorophenoxyacetic acid2,4-Dichlorophenoxyacetic acid is an organic compound with the chemical formula C8H6Cl2O3 which is usually referred to by its ISO common name 2,4-D. It is a systemic herbicide which kills most broadleaf weeds by causing uncontrolled growth in them but most grasses such as cereals, lawn turf, and grassland are relatively unaffected. 2,4-D is one of the oldest and most widely available herbicides and defoliants in the world, having been commercially available since 1945, and is now produced by many chemical companies since the patent on it has long since expired.
Special reconnaissanceSpecial reconnaissance (SR) is conducted by small units, such as a recon team, made up of highly trained military personnel, usually from special forces units and/or military intelligence organizations. Special reconnaissance teams operate behind enemy lines, avoiding direct combat and detection by the enemy. As a role, SR is distinct from commando operations, but both are often carried out by the same units.
Army of the Republic of VietnamThe Army of the Republic of Vietnam (ARVN; ; Armée de la république du Viêt Nam) composed the ground forces of the South Vietnamese military from its inception in 1955 to the Fall of Saigon in April 1975. At the ARVN's peak, an estimated 1 in 9 citizens of South Vietnam were enlisted, and it had become the fourth-largest army in the world composed of Regular Forces and the more voluntary Regional Forces and the Popular Force militias. It is estimated to have suffered 1,394,000 casualties (killed and wounded) during the Vietnam War.
Red River DeltaThe Red River Delta or Hong River Delta (Châu thổ sông Hồng) is the flat low-lying plain formed by the Red River and its distributaries merging with the Thái Bình River in northern Vietnam. Hồng (紅) is a Sino-Vietnamese word for "red" or "crimson". The delta has the smallest area but highest population and population density of all regions. The region, measuring some is well protected by a network of dikes. It is an agriculturally rich and densely populated area. Most of the land is devoted to rice cultivation.
