Answer:
C
Explanation:
the first 2 choices aren't even systems at all, and D is specifically talking about the water and not mentioning animals/plants at all.
hope this helps!
Answer:
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One of the amazing things about alternative energy resources is that they are renewable, unlike fossil fuels. The use of fossil fuels, such as coal and natural gasses, can contribute a lot to pollution since fossil fuels are usually processed through factories and plants. With water, wind, and solar energy, it is much easier to gain electricity with those methods rather than others, and much cheaper.
