To economists, the main difference between "the short run" and "the long run" is that:

Multiple Choice

• fixed costs are more important to decision making in the long run than they are in the short run
• in the long run, all resources are variable while in the short run, at least one resource is fixed
• in the short run all resources are fixed, while in the long run all resources are variable
• in the short run all resources are variable, while in the long run all resources are fixed
• the law of diminishing marginal returns applies in the long run but not in the short run