which is the largest organizational level found in one coral reef?\norganism\npopulation\necosystem\nbiome

Brief Explanations:

An organism is an individual living thing. A population is a group of the same - species organisms. An ecosystem is a community of different species interacting with their physical environment. A biome is a large region with distinct climate and characteristic plant and animal communities. In a coral reef, the ecosystem encompasses all the living organisms (corals, fish, etc.) and their physical environment (water, rocks, etc.), which is larger than an organism or a population. A biome is much larger than a single coral - reef area.

Answer:

ecosystem