Our analysis of production and cost begins with a period economists call the short. run. Theshort run in this microeconomic context is a planning period over which the. managers of a firm must consider one or more of their factors of production as fixed.
Sharks have two sets of paired fins on the sides of their body, in the same general position as the main wings and horizontal tail wings of a plane. The shark can position these fins at different angles, changing the path of the water moving around them.
Dorsal fin. Dorsal fin of a shark. A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fish, cetaceans (whales, dolphins, and porpoises), and the (extinct) ichthyosaurs. Depending on the species, an animal may have one or two of them.