Humans do not see the infrared or ultraviolet forms of light.
mayonnaise
Carotene will fluoresce in UV light, but the "colour" of the fluorescence is infra red and cannot been seen by the human eye.
Yes it can I believe it can be seen with your eyes. It can be seen in colour through a telescope.
The colour that is best seen in the dark is... Black
1666
Pink
reddish pink
grey
None
Blue.
The only colour a cheetah has that i have seen is orangey yellowy colour with black poker dots.
white in colour with a slimy texture.. colour changes can be seen between various species..