The correct answer is:
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→ " commensalism" .
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Note: "Commensalism" refers to a symbiotic relationship {"symbiosis"} between two (2) organisms — in which one organism benefits and the other organism is neither helped nor harmed.
{ i.e. " +, 0 " ; that is: "plus" sign for "one organism benefits" ;
"zero" sign for "neutral" ;
(in that the other organism is neither helped nor harmed.}.
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In the example given in the question, the two (2) organisms are:
1) the barnacles; and: 2) the shellfish.
The barnacles benefits by given a place to attach for the purpose of transportation (by using the shellfish to "cling to"}.
The shellfish are neither helped (benefitted in anyways from the attachment from the barnacles— nor are the shellfish harmed in any way.
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Hope this answer helps you!
Best wishes in you academic pursuits
— and within the "Brainly" community!
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