Why does the cord of an electric heater not glow while the heating element does?

The heating element of an electric heater is a "resistor", the cord which conducts the electricity is not.

The resistance of the element of an electric heater is very high. As current flows through the heating element, it becomes red hot and glows. On the other hand, the resistance of the cord is low. It does not become red hot when current flows through it.