Question

what happens if all limiting factors for a population are at the optimum level for an extended period? populations grow quickly. populations begin to die off. populations stop to grow. nothing significant happens.

Explanation:

When all limiting factors (like food, space, etc.) for a population are at optimum levels, there are no constraints on population growth. In such a scenario, the population can reproduce and thrive without limitations.

Answer:

Populations grow quickly.