Maps do not have to be in color but color helps make interpretation easier.
all the colors
The Four Color Theorem states that any map can be colored with at most four colors such that no two adjacent regions have the same color. This means the least amount of colors that can be used on a map is four.
physical,political
a Map key is important because it helps you understand a symbol, label, or explanation. (thanks for supporting my answer please leave comment if you like it or not!:-)
A map title is important because you wouldn't know what the map is about without it.
It is a map that indicates temperatures in an area by using different colours and a key to indicate the temperatures the colours represent.
Mainly different colours.
It uses different colours, with a legend telling you which colours represent which height.
cartogram
blah blah blah
Blue - water Green - vegetationWhite - non-forested areaRed - land grid and important roadsBlack - small roads/trails, railways, boundaries etc
A legend describes the meaning of lines, symbols and colours used on the map.
all the colors
I believe it is "cartogram".
It is used to see the colours that it gives off, if you know the colours you then know what atom it is.
the colours
Green (land), brown (land/mountains), White (snow), and depending what map - multi-colours such as pink and purple