Which of the following best explains what would happen if there were no primary consumers in an ecosystem?

the population of producers would decrease, while less energy would be transferred from autotrophs to heterotrophs.
the population of producers would increase, while carnivores would lose their energy source.
the population of producers would increase, while more energy would be transferred from the secondary consumers to the producers.
the population of producers would decrease, while herbivores would adapt to using heterotrophs as an energy source.

The population of producers would increase, while carnivores would lose their energy source.

Explanation:

In a food chain producers belong to the lowest trophic level. They have the highest amount of energy in the food chain. The producers are consumed by the primary consumers. The primary consumers are consumed by the secondary consumers. The secondary consumers are consumed by top carnivores or tertiary consumers.

If there were no primary consumers in the ecosystem then the population of producers will increase as there will be no group of living beings which can consume them. But the population of carnivores will decrease as the population of primary consumers will not be available as food source.

The population of producers would increase, while carnivores would lose their energy source.

Explanation:

In a food chain producers belong to the lowest trophic level. They have the highest amount of energy in the food chain. The producers are consumed by the primary consumers. The primary consumers are consumed by the secondary consumers. The secondary consumers are consumed by top carnivores or tertiary consumers.

If there were no primary consumers in the ecosystem then the population of producers will increase as there will be no group of living beings which can consume them. But the population of carnivores will decrease as the population of primary consumers will not be available as food source.

The population of producers would increase, while carnivores would lose their energy source.

Explanation:

In a food chain producers belong to the lowest trophic level. They have the highest amount of energy in the food chain. The producers are consumed by the primary consumers. The primary consumers are consumed by the secondary consumers. The secondary consumers are consumed by top carnivores or tertiary consumers.

If there were no primary consumers in the ecosystem then the population of producers will increase as there will be no group of living beings which can consume them. But the population of carnivores will decrease as the population of primary consumers will not be available as food source.