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.
In the same family (Percidae) as walleye and sauger, yellow perch have two dorsal (top or back) spinyâray fins. The front dorsal fin has 12 to 14 spines (a stiff, sharp support of the fin) and the back. dorsal fin has two spines and 12 to 14 rays (soft, flexible support).