Q. The relationship between a reef-building coral and zooxanthellae can be characterized under which of the following categories?

[A] Amensalism

[B] Commensalism

[C] Mutualism

[D] Competition

Answer: C
  • Shallow water, reef-building corals have a symbiotic relationship with photosynthetic algae called zooxanthellae, which live in their tissues. The coral provides a protected environment and the compounds zooxanthellae need for photosynthesis. In return, the algae produce carbohydrates that the coral uses for food, as well as oxygen. The algae also help the coral remove waste. Since both partners benefit from association, this type of symbiosis is called mutualism.

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