Can someone me with this multiple choice question? (biology)

62. I, there is less d.o. Eutrophication causes dead zones (areas where no fish can survive) in the water because the decomposition of the algae requires oxygen. An example of this can be seen in the Gulf of Mexico.
63. A. tempature. Corals depend on a specific tempature for their survival. The change in tempature is the direct cause of corals going into shock and releasing zooxanthellae. It's actually very sad, many of our reefs have died as a result of climate change.

The answer would be abrasion.