Competitive exclusion occurs when "<span>a. organisms attempt to fill the same niche" mostly due to the fact that they are competing over the same food source, which is always limited in some way.</span>
I believe the answer is: a. organisms attempt to fill the same niche
Competitive exclusion refers to a principle that stated that two organisms who compete for the same resources cannot had the same constant population values together. This mean that when one of the organisms experiencing a rise in population, the other competing organism would experience a decline in population and vice versa.
