Explain how carnivores might be affected if the main plant species in a community were to disappear

Carnivores (only eat meat) eat herbivores (only eat plants) to survive, Herbivores eat plant to survive. So with out the main plant species to eat eventually herbivores will run out of food and die, when that happen the Carnivores will run out of food and die. Us humans are both herbivores and carnivores so if this were to happen the ending result would be extinction for all life forms Plants, Animals and Humans.