First, we have C6. The C represents Carbon, and there are six atoms present. Next, we have H12. The H represents Hydrogen, and there are twelve atoms present. Finally, we have O6. The O represents Oxygen, and there are six atoms present.
Combined, these atoms make our lovely glucose, a form of sugar that plant produce in the process of photosynthesis.
FYI most of this information can be found on the lovely search engine called Google. ;)
