Answer: molecule
Explanation: common knowledge
food chain:The simplest representation of energy in a community. At the base is energy stored in plants, which are eaten by small organisms, which in turn are eaten by progressively larger organisms; the food chain is an oversimplification in that most animals do not eat only one type of organism.
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food web:the interconnected feeding relationships in an ecosystem. These relationships can be complex; some organisms may feed on more than one trophic level, or changes may occur depending on a species' life history stages or the availability of food.
I would say the last one. Yes, the coral reef in the south is being threaten but, it’s not the only one. Many other reefs are being threatened. Why? To find the problem to this reef you need to find the problems of other reefs and compare the data. Which ever the most problem cause you get rid of that first.
