Coral reefs are at risk due to... (choose all that are correct) physical damage from careless divers and boats
Overfishing of herbivorous fish
Increased nutrient runoff from land
Rising sea temperatures
pollution
dropping pH of the ocean
Overgrowth of algae
Rising sea levels
extreme weather
increased sediment load from land and sea

The answer is the dropping pH of the ocean

Explanation:

The ocean absorbs tons of carbon dioxide (Co2) from the atmosphere which changes the chemistry of the water. The ocean is naturally Alkaline but, as the oceans absorb Co2 it turns into carbolic acid. This doesn't make the ocean's immediately acidic but it is causing them to be gradually less alkaline. Since the direction of change is near the acid end of the scale, the process is known as ocean acidification. The coral reefs need the alkaline environment and can feel when the environment changes and when the ocean becomes to acidic for them it kills off the coral.

what's the rest of the question

well we can't tell you because we cant see the time give a screen shot or something.