Final answer:
A chafing dish can use steam, electric heating elements, or a gas burner to keep food hot, each method relying on different forms of heat transfer such as conduction or convection.
Step-by-step explanation:
A chafing dish keeps food hot through various methods such as steam, electric heating elements, or a gas burner. Each of these methods uses the concept of heat transfer to maintain the temperature of the food. Steam provides a consistent source of heat through conduction and convection, electric heating elements utilize electric energy to produce heat through resistance, and gas burners create a direct flame that warms up the chafing dish. When using a chafing dish, you can control the level of heat to ensure the food stays at the desired temperature.