In our widget example, we will assume that the fixed cost for the stapler, pen, and âfactoryâ is $10 and the cost of each worker hired is $5 per worker. Since fixed costs are constant, the firm incurs $10 regardless of the level of output. Labor is the only variable cost computed by $5 times the number of workers.
How Bull Sharks Can Live in Both Ocean and Fresh Water. Although there are a handful of species that live in freshwater, we tend to think of sharks as being ocean dwellers. But there is also a very unique shark that can live in both ocean and fresh water estuaries and lakes: the Bull Shark.
Some researchers say that sharks mistake surfers on surfboards for seals and that's the reason they attack them. Sharks are attracted to movement. If someone is splashing in the water while swimming, the shark will relate that to a struggling fish or seal, easy prey.