"These are usually secured by mortgages, deeds of trust, land contracts, or other types of real estate liens. Interest rates for residential mortgages loans may be fixed or variable. Repayments of…

“These are usually secured by mortgages, deeds of trust, land contracts, or other types of real estate liens. Interest rates for residential mortgages loans may be fixed or variable. Repayments of principal may be set up for full amortization, negative amortization, or partial amortization with a balloon payment at a specified rate.” What are these?