A Sedentary sea anemone gets attached to the shell lining of hermit crab . The association is
A) Ectoparasitism
B) Commensalism
C) Amensalism
D) Both B and C

Hint: In cultural anthropology , sedentism or sedentary is the practice of living in one place for a long time.

Complete answer:
>Interspecific interaction arises from the interaction of populations of two different species.It can be beneficial , detrimental or neutral to one species or both .
>Commensalism is the interaction in which one species benefits and the other is neither harmed nor benefited.
>An orchid growing as an epiphyte on the mango branch , due to the interaction between them orchids get the benefit wild mango branch is unaffected.
>The cattle egret and grazing cattle in close association , a site you are most likely to get if you live in a farmed rural area is a classic example of commensalism.
>The egrets always forage close to where the cattle are grazing because the cattle , as they move , stir up and flush out the vegetation insects it otherwise might be difficult for the egret to find and catch . So it is beneficial for the egret.
>A Sedentary sea anemone gets attached to the hermit crab is also an example of commensalism.

Hence the correct answer is option ( B ).

Note:There is no such habitat or a situation where a single species can live isolated . The minimum requirement is one more species on which it can feed . Even a plant species which makes it on food cannot survive alone; it needs soil microbes to break down the organic matter in the soil and return the inorganic nutrients for absorption.