Which population would be least likely to survive a change in its ecosystem? A:bacteria that can grow in both hot and cold environments

B:grasses that can grow in normal or contaminated soil

C:brown bears that can eat a variety of different kinds of food

D:koalas that eat only eucalyptus leaves

D

Explanation:

lIf the change in the ecosystem occurs, then it would effect the weather, temperature, and the abiotic factors. So, we can see that the bacteria could survive in any sort of temperature. So, A can't be it. Also, B can't be it because the grass can grow in any sort of soil, even if the soil is contaminated. C cant be it because even if the change in the envoriment (temperature, contaimination) kills of one of the brown bear's food source, they can still have other things they can eat. But, if the weather gets too hot or the soil gets contaimnated and kills off the ecalyptus plants, the koala has nothing  else to eat. So, best answer is D.