What is your knowledge & understanding on health insurance?

I am studying this in med. assistant class. So to those who work in this field, what is medical insurance in a nutshell?
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Health insurance provides health care coverage for individuals ......there is a huge monthly premium that insurers must pay for health benefits.....such as hospital coverage for an illness or accident, regular doctors visits, and for pharmaceutical drugs. The overall costs are astronomical in the United States.......... so many people cannot afford the monthly fees to help them live a normal life.....as many people need the insurance to help them pay for maintenance drugs they need to survive. Such as illnesses as simple as Asthma and arthritis.......... people need to have daily medicine....called preventative medicine which is very costly.
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