The problem is where. Photosynthesis is not a location. It is a process plants use to provide food for themselves. I'm not a biologist, but this how I imagine the sentence could be corrected.
<em>Answer</em><em>: </em><em>Photosynthesis is the process by which plants transform the environmental elements of sunlight, carbon dioxide, and water into needed carbohydrates. This process is accomplished by the green pigment in the plant identified as the chemical chlorophyll. </em>
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I think I've fixed the problem, but I've made the thought more complex by simplifying it, if that makes any sense. If someone else answers this, I'd likely take that answer. Anyway, what I've written does fix the problem.
