How much you can cover will depend on the size of the essay, but regardless of the length, you should always write concisely and on topic. A standard 1,500-word essay, for example, will generally accommodate three to four paragraphs, not including the introduction and concluding paragraph. Each paragraph should have its own topic that relates to and supports your thesis. You should have no more than one or two quotes or paraphrased statements in support of your position, not in place of your own thinking. Quotes and paraphrasing must have proper citation.
Most plants are autotrophs, organisms that synthesize all their own organic nutrients and do not rely on other organisms for food. The reason that plants are autotrophic is that they carry out photosynthesis in their leaves. In the process of photosynthesis, the plant converts water, carbon dioxide, and light energy into oxygen, sugars, and more water. The oxygen is released into the surrounding air through the stomata, and the sugars (organic nutrients) are transported throughout the plant body to areas of growth and storage.