Answer:
Closely related species occupying the same niche.
Explanation:
Competitive exclusion principle states that the two species cannot exist together if they share the same resources. The one species completely exclude the other species from their niche.
Competitive exclusion principle generally occurs between the species that occupy the same niche and are closely related with each other. The competitive exclusion principle first explained between the species <em>P. aurelia </em>and <em>P. caudatum.</em>
Thus, the correct answer is option (B).
Answer:
The variation might occur in the population that leads to the evolution of the species. This variation may occur due to natural selection, mutation or recombination.
The variation might change the genotype and allelic frequency of the population and might also change the phenotype of the individual in the population. The breeding adults of the left mouthed in 1981, 1987 and 1990 shows variation and was equally opposite phenotype which is more common in the population.