Answer:
B) realized niche
Explanation:   
The ecological niche refers to all the environmental factors that influence the growth, survival, and reproduction of species. These factors also include the interaction between species. The term ecological niche refers to the fundamental niche or the realized niche.    
- The fundamental niche refers<u> only</u> to factors or physical conditions under which a species can live and survive in the <u>absence of any interaction with other species.
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- The realized niche refers to the restricted conditions in which a species can live and survive as a result of <u>environmental conditions and the interaction with other species</u><u>.
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When an inferior competitor is excluded by the superior competitor, this is known as competitive exclusion. This occurs when there is not habitat differentiation, and both species can not share the same niche. In this case, the effective or realized niche of the dominant species completely occupies the fundamental niche of the inferior competitor.        
  In the exposed example the organism is able to occupy a niche in the presence of competitors, which is the clue for us to classify this niche as a realized niche. The organism needs to interact in a certain way with its competitors. There is an interaction between taxonomic groups, or between individuals. 
 
        
             
        
        
        
The answer is skin. The skin is also the largest organ in the body and has the most contact with the outside environment. It is estimated that there are approximately 205 identified genera of bacteria alone on the skin. This normal flora of the skin play significant roles in the body such as augmenting immunity. 
 
        
             
        
        
        
Gravitational potential energy
 
        
             
        
        
        
The ear has the tinest bones in the body. There are three bones in the ear. Hopes this helps you.