Answer: ecosystem
An ecosystem is a community of living and non-living components. A coral reef is an aquatic ecosystem which is formed by a continuous walls of calcium carbonates released by living animals they get combine to form rocks. These rocks and walls are collectively called as hard stony corals. These hard stony corals provide shelter to many aquatic animals like fishes. As the water is the chief abiotic factor along with coral walls and rocks which help in the survival of living organisms therefore, ecosystem is the largest organizational level found in one coral reef.
Answer:
I think option B and C is correct answer
When it triggers an abnormal or vigorous immune responce, treating the antigen that would normally cause no threat as something harmful.
B: receptor, sensory, interneuron, motor, effector
