Why Is the Barnacle Chthamalus Found Only in the Upper

question 65

Multiple Choice

Why is the barnacle Chthamalus found only in the upper regions of the intertidal zone?

• A) It cannot live at the bottom of the zone where oxygen levels are low.
• B) Interference competition from another barnacle, Semibalamus, prevents adults from persisting at the bottom of the zone.
• C) Exploitative competition from another barnacle, Semibalamus, prevents adults from persisting at the bottom of the zone.
• D) Its larvae are able to survive only in the upper intertidal zone.

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