Question

what factor is contributing the most to the decline of coral reefs in oceans?

increased ocean acidity

reduced harmful radiation

decreased ocean pollution

cooler ocean temperatures

Explanation:

Coral reefs are sensitive to environmental changes. Increased ocean acidity, caused by the absorption of carbon dioxide, disrupts the calcium carbonate structures that corals build. Reduced harmful radiation would not harm corals. Decreased ocean pollution is beneficial. Cooler ocean temperatures are not a major factor compared to acidity.

Answer:

increased ocean acidity