Scientists observed that the populations of top-level consumers in a particular ecosystem were rapidly decreasing. Further studies revealed that there was also a decline in producer productivity. Which other changes did the scientists most likely observe in the ecosystem? increased producer diversity

decreased population size at all levels

decreased primary consumer populations only

increased primary and secondary consumer diversity

The correct answer is - decreased population size at all levels.

Explanation:

A decrease in the productivity of producers of an ecosystem will lead to a decrease in all other organisms of the ecosystem including top-level consumers to the bottom-level producers due to the fact that producers provide energy and food to primary consumers.

It is because they are the only organisms that convert the sunlight to usable energy and food that transfer from one trophic level to other, so if the population of producers or their productivity will decrease then there will be decreased population size at all levels.