Answer:
I think It's D
Explanation:
If it's not D then it's B
Answer:
Without the model, we can't help you. But a healthy coral reef would most likely have some kind of productive ecosystem.
Explanation:
I would assume the the diagram includes a reference to fish, algae or other plant-like life, and the coral itself. The coral polyps are in a symbiotic relationship with algae; the algae provide the polyps with energy via photosynthesis and the polyps build "homes" for the algae and other species living in the reef (the "home" for algae is literally the coral reef).
Other species like animal life use the reef as a place of protection against larger predators. Fish frequent reefs since many types of aquatic predators dislike shallow waters and coral reefs provide plenty of nooks and crannies to hide inside.
Explanation:
Humus content is another characteristics
