explain this sentence "When the voltage across the diode tends to increase, the current through the diode rises out of proportion and causes a sufficient increase in voltage drop across the resistor. "?

kindly explain in simple words?

If the input voltage increases, the current through R & diode also increases. This increases the voltage drop across the zener diode. This is because in the breakdown region, Zener voltage remains constant even though the current through the zener diode changes. Similar in the case of decrease in voltage.Thus any increase/decrease of the input voltage results in increase/decrease of the voltage drop across R widout any change in voltage across zener diode. Hence, the zener diode acts as a voltage regulator.