The correct answer should be<span> D) conserving natural resources without harming the environment
Instead of using new resources, you can use the waste from previous production and recycle it for the sake of creating something else, which preserves the resoruces and doesn't harm the environment.</span>
Answer: C. is your answer
In the open ocean, especially around the surface, one of the main sources of food for fish would be the algae that grow at the surface & photosynthesize with the sun. Without fish to regulate the amount of surface algae, they overgrow and block the sun from the organisms on the coral reef.
Without sun, the reef is not able to sustain themselves & it's down hill from there.
I hope this helps!
The answer is Eukaryotic cells