Answer:
Cloud condensation nuclei or CCNs are small particles typically 0.2 µm, or 1/100 the size of a cloud droplet on which water vapor condenses. Water requires a non-gaseous surface to make the transition from a vapour to a liquid; this process is called condensation.
I recently wrote a paper on animal testing
Pretty sure it was Galen
Use the equation for density :
Density = mass / volume
Density = 120 / 480
Density = 0.25
