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.
The anal fin on the underside of the shark serves the same purpose. It is often said that the anatomy of an airplane is very similar to that of a shark. When you visualize this in your mind you can see it is very true. There is a tail and the wings to help balance everything and to give it speed.