As long as two species occupy different niches, there is:

Explanation

The correct answer is that there is no competition when two species occupy different niches. A niche defines how a species interacts with its environment, including its habitat and resource use. When niches differ, species reduce direct competition by exploiting distinct resources or ecological strategies. Therefore, occupying different niches allows coexistence without the need for competing for the same resources. The other options are incorrect because they pertain to genetic concepts (gene linkage and polymorphism) or misunderstand the ecological principle of niches (competition).