Barnacles attach to shellfish for transportation. the shellfish is not or harmed. this is an example of_

The correct answer is:

                       →    " commensalism" .

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.}.

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.

Hope this answer helps you!

     Best wishes in you academic pursuits

               — and within the "" community!

explanation: