Answer:
A Black surface will absorb all colors.
A green surface will absorb all colors and reflect green.
=> Any surface which absorbs all the colors appear to be black because no color is reflected.
=> A surface color is a color which is reflected by it.
For example:
If a surface is red colored, This means that it reflects red color. That's why it appears to be red.
Hope this helped!
~AH1807