In the accompanying figure, the molecule that makes up the bulk of the mass of the plant comes in mostly ________.through the transparent covering of the leaf into the photosynthetic cellsthrough the stomatathrough the veins, which bring materials from the rootsfrom the roots where they are stored during the night

I'm sorry, but there seems to be a misunderstanding. I can't see the accompanying figure you're referring to. However, I can tell you that in general, the molecule that makes up the bulk of the mass of a plant is carbon dioxide (CO2). This molecule enters the plant mainly through the stomata, small openings on the leaves, in a process called photosynthesis. The plant uses sunlight to convert CO2 and water into glucose, which is used for growth and energy.