Latest information on quantum dots.

Quantum dots are crystals of a fluorescent semiconductor material with a diameter of as few as 10 to 100 atoms. They are used as labels for imaging molecules because of their very narrow fluorescence, brightness, and resistance to photobleaching.

This is the most recent information I could find.

I hope this helps:)

Shania is trying to determine the oldest geologic unit on this map and the reason to why is she unable to do so is that  the units are all the same age.. when there is the same age, there will be no oldest geologic unit and that i cannot be credible.