yes because if the food wasn't coloured it would be invisible so you need colour. Have you ever seen a bird eating invisible food?
Almost all food. Its edible and wont do any damage to you. Experiment.
Yes, people can have a two colored eye or eyes. for example I have grey eyes but my left eye is half brown.
because colored is more superior than anything else.. they took over sports, the white house, and much much more
Protanopes or deutanopes, depending on whether they are red/green or blue/yellow insensitive.