1/2 of a radioactive substance will remain after 3 half lives.
They can also use carbohydrates so I don't know
DNA and RNA both produce proteins, but RNA copies itself and moves out of the nucleus while DNA stays inside the nucleus and produces proteins. Also DNA helps more in cell division, while RNA helps in making proteins.
Plants get the carbon dioxide they need from the air through their leaves. It moves by diffusion through small holes in the underside of the leaf called stomata. These let carbon dioxide reach the other cells in the leaf, and also let the oxygen produced in photosynthesis leave the leaf easily.
