Arm Vs Fixed Mortgage Why Are Mortgage Loan Interest Rates Higher For Fixed Rate Mortgages Held For Longer Periods Of Time?

Why are mortgage loan interest rates higher for fixed rate mortgages held for longer periods of time? - arm vs fixed mortgage

Sorry if this sounds like a silly question, but I do not understand. For example, say why 30 years fixed mortgage interest rates, the highest rates of mortgages, compared with a 15, and why are 15 years fixed-rate mortgage is higher than the mortgage rate variable? It seems that the lender to accept a higher risk with an ARM versus a mortgage fixed interest rate, and they should pay a higher rate (eg, comparing this situation with a major car loan a used car loan - the risk is in a car loan?
Risk can mean a fixed rate equivalent to 30 to 15 - most of borrower still does not understand, however, his arm was so low.