In a local lake, the black bass was over fished one year. the following year, there was a industrial pollution incident that killed off another large portion of the black bass. this led to the demise of black bass in this lake. as a result of human activities, what happen to the other fish species in the lake after the demise of the black bass? a) the other species became extinct b) numbers decreased when competition decreased c) numbers increased when competition decreased d) demise of black bass had no affect

Not sure if there is enough information but here goes:

It is definitely:

not A:  The question does not state that pollution affected the other populations so you can't assume that.

not B:  a decrease in competition would lead to an INCREASE in numbers, not decrease.

maybe D, but probably not:  this answer would mean that the different fish populations are not likely to affect each other; in a stable ecosystem that is unlikely.

best answer C:  decreased competition for resources would likely increase the availability for other organisms in the ecosystem.

Hope this helps!