Economies of Scale and Long Run Average Cost (LRAC) 1  In the long run all costs are variable and the scale of production can change (i.e. no fixed inputs) 2  Economies of scale are the cost advantages from expanding the scale of production in the long run. The effect is to reduce average costs over a range of output. These lower costs represent an improvement in productive efficiency and can give a business a competitive advantage in a market.
Tiger sharks (pictured) are among the 17 species that appear to lack color vision. Sharks may be able to smell blood from miles away, but they probably don't know how red it is: New research suggests sharks are color-blind.
Sharks' eyes are protected when attacking prey. Also unlike humans, shark eyelids serve to protect the eye when attacking prey. Some sharks have a nictating membrane, or a clear membrane that covers and protects the eye when a shark bites its prey. Sharks like the Great White, lacking a nictating membrane, roll their pupils back in their heads for protection when feeding.