The answer to this question is D.
Climate change is causing the Earth to gradually increase in temperature, this is causing the warming waters.
Coral has this beneficial relationship with this algae called zooxanthellae. The coral provides a home where the algae provides some nutrients. Zooxanthellae uses photosynthesis to get its own food (It's not getting any inside a coral polyp!)
When there is an increased amount of sunlight there is more photosynthesis occuring, which means more and more algae.
To disprove C, the great barrier reef is KNOWN for its biodiversity. Theres LOTS goin' on down there.
Hope this helps!
The planting of cover crops can reduce the effects of wind erosion on topsoil beds.
Venus orbits the Sun every 224.7 Earth days. It has a synodic day length of 117 Earth days and a sidereal rotation period of 243 Earth days. As a consequence, it takes longer to rotate about its axis than any other planet in the Solar System, and does so in the opposite direction to all but Uranus.
It helps with the worlds water supply.