Final answer:
The remaining level of unemployment that occurs even when the economy is healthy is called structural unemployment. This type of unemployment is caused by a mismatch between the skills and qualifications of available workers and the requirements of available jobs.
Step-by-step explanation:
The remaining level of unemployment that occurs even when the economy is healthy is called structural unemployment. This type of unemployment is caused by a mismatch between the skills and qualifications of available workers and the requirements of available jobs. It typically exists even during periods of economic growth and can occur when industries become obsolete or when workers lack the necessary training.