Allergies are the result of a hypersensitive immune system. The allergic immune system misidentifies an otherwise innocuous substance as harmful, and then attacks the substance with a ferocity far greater than required.
Laying off an employee is different from firing an employee. Firing means letting a worker go for any reason, whereas a layoff refers to an employment termination based on economics, usually involving more than one worker.
As a result, computer companies expand production while typewriter companies lay-off workers. This is an example of a. structural unemployment created by efficiency wages. b. cyclical unemployment created by a recession. c. frictional unemployment created by a sectoral shift in demand.