Question

What would happen if all carnivores were killed?

Answer 1

herbivores animals population would have increased..
as herbivores animals increase,the grass or vegetation get exhausted

Answer 2

They will eat themselves into starvation.Even if you remove all the carnivores, there are still quite a few omnivores, and omnivores eat fruits and vegetables but they eat meat too. For example, birds eat seeds, but they'll eat bugs too.