Final answer:
The provided statement is false; the long run is characterized by the flexibility to change all costs, including plant capacity, not just the intensity of use of a fixed-size plant.
Step-by-step explanation:
The statement provided in the student's question misunderstands the concept of the long run in economics. In fact, the statement is false. The long run is a period of time in which all costs, including plant capacity, are considered variable. This means that firms have the flexibility to alter their fixed inputs, like the size of a factory, to better fit their production needs. In other words, the long run allows for the adjustment of capital assets, labor, and new technology. This is opposite to the short run, where at least one input is fixed and cannot be changed.
In the long run, a firm can build new factories, purchase new machinery, or it can choose to shut down existing operations. This flexibility in decision-making is what differentiates the long run from the short run. An example to illustrate this point could be the factory lease mentioned. If a firm has a one-year lease, the period after that year constitutes the long run, since the firm is no longer tied to the fixed input of the factory's capacity dictated by the lease and can make changes to it.