a. All producers are removed;

b. All organisms of herbivore level are eliminated; and

c. All top carnivore population is removed

solution –

1. If producers are removed then  organisms are dead. There won’t be primary productivity and No biomass would be available for the next trophic levels.
2. organisms depending on herbivores will die. Producers would flourish and primary productivity would rise .
3. there will be an increase in the population of herbivore which would start to destroy producers  leading to ecological disbalance.