If I am not wrong, I believe the answer is Producers. The reason as to why I say that producers is the answer is because in every food chain, there needs to be a base. That base is what provides the starting energy that will later on move up in the food chain.
Why did he??????
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Science
This is true because humans can only know so much due to unexplored lands, water depth, and evidence of extinction being hidden.
A is your answer I believe because they do indeed provide a way to review other scientists work and or experiments
