Concave mirrors- like the bowl of a spoon. The image formed is enlarged and upright.
We can see object because light is being reflected from those objects. The color of the object depends on the frequency of light being reflected. White light ( which contains all colors, think prism) when striking an object will absorb some of the colors, while reflecting back others- we see reflected light.
Refraction of light- as light travels from one medium to another it will change speeds, object appears to be bent.