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.
Unlike other species of shark, the bull shark is able to tolerate fresh water. As a result of this, it is not uncommon for bull sharks to be found in freshwater rivers and lakes. In recent years there have been a number of reported attacks by bull sharks in fresh water and also river mouths. Shark attacks on humans however are rare and often the result of mistaken identity. The onus is always on the individual to ensure his or her safety.