Answer:
D. Temperature
Explanation:
Several environmental factors affect how dense or sparsely populated an ecosystem is. These factors include; temperature, pH, predation, food, etc. The presence or absence of this factors can either limit or enhance the number of populations that exists in an ecosystem.
According to this question, Lake trout are reported to be found in the Great Lakes because they can only live in cold environments. Since temperature is a measure of how hot or cold a substance/place is, this means that this exemplifies how a number of populations an ecosystem can support is limited by TEMPERATURE.
