Answer: Herbivores are the primary consumers in the food chain as they feed on the producers like plants. Carnivores feed on herbivores and so they are the secondary consumers or predators of herbivores.
If the herbivore population is increased, initially there will be more availability of food for the carnivores. Due to this, the size of carnivore population increases. As a result, gradually the herbivores now start depleting and they reach to a point that they are not sufficient to feed all the predators.This eventually causes the death of predators so that again the population of herbivore can reach the equilibrium.