A niche is a habitat and way of life to which a particular organism is adapted. It is the role of a particular species within an ecosystem, including all aspects of its interaction with the living and nonliving environments.  Habituation is a common form of simple learning, defined as a decline in response to a repeated stimulus. The ability to habituate is adaptive. Humans habituate to many stimuli: city dwellers to traffic sounds, and country dwellers to the sounds of nature. A biome is a terrestrial ecosystem that occupies an extensive geographical area and is characterized by a specfic type of plant community. A community is all the interacting populations within an ecosystem. Terrioriality is the defense of an area in which important resources are located. 

A species generalist can survive in a wide variety of environmental conditions and make use of varying resources. Honey badgers are generalists because they eat proportionally smaller amounts of many types of food over their lifetime. The other species listed are specialists and eat a proportionally large amount of one or few types of food over their lifetimes.

Mangrove roots grow densely in salt water and form nurseries for young marine life before they are large enough to move into more open waters. Mangroves have many special adaptations for surviving in marshy environments.

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.