A species' niche is its unique role and position in its ecosystem. This could be the type of home it builds, the food it eats, or anything unique to that species' position in life. In balanced ecosystems, species' niches are diverse with only minor overlap to reduce unnecessary competition.

Evolution is the process that creates diverse species. Though evolution can be tracked through fossils, it can also be observed in modern times. A habitat is an organism’s home, which provides the organism food, water, and shelter. Last, an ecosystem is a community of organisms (plants and animals) and their nonliving environment (air, soil, water).

“Endemic” is the only answer choice that makes sense.  An endemic species is defined as a species found specifically in one region and nowhere else. The words "endangered" and "extant" refer to unhealthy species, and the question specifically uses the word healthy to describe the species. The word "eutrophic" has nothing to do with the question and relates to pollution related to algae blooms in nutrient rich biomes. 

The correct response is Competitive Exclusion Principle. This is the only answer choice that is specific to niches and competition. 

The correct response is Fundamental niche. This fundamental niche describes all the possible locations that a species can live. The term realized niche is where a species actually lives in response to its predator-prey and competitive relationships. The other two answer choices are made up terms.

Niche partitioning occurs when species develop different patterns of obtaining resources to avoid overlapping and over-exploiting the same resource. A classic example is in nest-height preference in birds. Some are more adapted for and prefer lower parts of the tree while others prefer the treetops. This eliminates some inter-species competition.

Adaptations improve an individual's chances of surviving and reproducing and are part of the natural selection process, not an end result. Inheritable variation and reproductive success, along with high reproductive capacity and differential reproductive success, are the observable factors supporting the theory of natural selection. Mutations are variations in the genes of individuals and are part of the natural selection process. 

Taiga, otherwise known as boreal forest and found in Northern Europe, North America, and Northern Asia, contains mostly pine trees and other evergreens. The soil type is acidic, as is preferred by those trees.

A plant that starts to sprout directly after a disturbance such as a forest fire is a primary successor. These plants are called pioneer species, but their location in the succession is in the primary spot (one example of such a species is the Yosemite Sequoia.)

The competitive exclusion principle states that two species cannot occupy the same niche without one of them driving the other extinct. Thus, species either occupy a slightly different niche, or occupy a different physical location from one another, an evolutionary strategy known as niche partitioning. 

Because two species cannot exist within the same niche, if they are to occupy the same geographic space, they must use different resources, or one of them will be driven to extinction. This practice is known as resource partitioning.