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.
But they do have extra large livers, which provide some buoyancy and help keep them sinking to the ocean floor. But fresh water changes how much buoyancy the shark's liver can provide. The researchers found that when sharks swim in fresh water, they are two to three times less buoyant than when they swim in salt water. In order to keep afloat the same way they do in salt water, sharks would need livers eight times as largeâunrealistic for an organ thatâs already the largest in a sharkâs body.