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.
1 flat body like a stingray -- you can tell the shark is not a ray because the pectoral fins are not attached to the head.  They bury themselves in the sand or mud with only the eyes and part of the top of the body exposed.