Question

Barnacles are crustaceans that attach themselves to large marine animals

Answer 1

Answer:  [D]: " commensalism " .

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Explanation:

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Note:  The answer choices listed are examples of "symbiotic relationships" between 2 (two) different species; and these terms are using in biology—more specifically—within the sub-specialty field—ecology.

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In the example provided:

We are given two species:  1) barnacles;  and 2) whales;

in which the barnacles benefit ; and the whales aren't affected at all.

So one species (the barnacles) benefit; and the other species is "neither helped nor harmed".   In other words: "(+, 0)" —in which "+" represents one species benefiting; and the "0" meaning "neutral"—the other organism/species is neither helped nor harmed.

Let's review the answer choices:

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Choice [A]:  "predation" .  In this type of symbiotic relationship—also, known as "predator-prey relationship"—one species [the predator] benefits (+), while the other species [the prey] is harmed [wounded or killed and eaten.].

(−) .   In other words: "(+, −)" —in which "+" represents one species benefiting; and the "− " meaning "negative"—the other organism/species is harmed.

The example given in the question is NOT:  "(+, −)" ; so we can Rule out choice:  [A].

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Choice [B]: "parasitism" .  Like "Choice {A]" above, this is a:  "(+, −)"  symbiotic relationship.  The parasite is benefited (+) by living on and obtaining nutrients from the host organism, and as such, the host is being harmed by the parasite (−) .  Since this is a "(+, −)" relationship, we can rule out Choice: [B].

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Choice [C]: "mutualism" .  This is a "(+, +)"  symbiotic relationship, in which two organisms/species interact together in a way in which "Species A" benefits from "Species B" ; while "Species B" benefits from "Species A".

This is a "(+, +)" relationship; so we can rule out "Choice: [C]."

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This leaves us with the correct answer: Choice [D]:  " commensalism ";  

  →  the term that describes a "(+, 0)" symbiotic relationship ;

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Note: There is another type of symbiotic relationship known as "amensalism" ; which is a:  "(0, − )" relationship.

Note:  There are "science terms" (in the disciplines of biology and ecology.).

           In non-science related terms, what we colloquially refer to as "symbiosis"—or a "symbiotic relationship"—is actual somewhat like "mutualism" in ecology [see 'Choice:  C' above.].

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Hope this is helpful to you!

  Best wishes to you with your academic pursuits!

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