Green plants use light energy to grow. what would happen to plants in a dark greenhouse if they were lit only by green light

If we placed a plant in a dark greenhouse which contains only green light, so photosynthesis will not occur or very low quantity of photosynthesis occurs because plants absorb red and blue color lights for the process of photosynthesis while green color light is reflected by the plants due to the presence of of green pigment called chlorophyll.

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.