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.
Swim in a group. Regardless of the danger of sharks, you should avoid swimming alone. If sharks are present, however, it's even more important to travel with a buddy or a group. Sharks are less likely to approach and attack a group of people, and if one member of the group is attacked, help is immediately available. When diving, go straight to the bottom. 2  If you swim on the surface it will make you look like a fish. 3  If you see a shark, exit the water and alert others. 4  If the shark is aggressive, be prepared to fight (punch the shark in the nose).