Final answer:
The color green is typically used in laboratory settings to represent safety and might also signify full capacity, as illustrated by its usage with fluorescent green-dyed antifreeze in a radiator header tank.
Step-by-step explanation:
When addressing the question about which color represents the cylinder/contents and full capacity, it is important to consider the context of usage for colors in a chemical or laboratory setting. Typically, certain colors are used to denote specific properties or to provide visual signals for safety and identification. In this context, the color green is often associated with safety and is used to indicate that a chemical or substance is safe to handle under normal conditions, and it might also be used to signify the full capacity of a container such as when fluorescent green-dyed antifreeze is visible in the radiator header tank of a car. This usage is evident from the provided references, such as the one where green arrows indicate cooling in phase changes and green color is used for easy visibility in light conditions or for safety purposes as with antifreeze.