not all crabs have unusual colors, markings, or structure, although its not the crabs you usually see, there is still crabs with unusual colors, markings, or structure. For example: The Red Spotted Guard Crab, or the Blue Land Crab
There are actually many types of crab spiders. In order to help you learn the markings of a crab spider you must first know what specific spider you are looking for.
what is the body structure used for protection of a crab
what is the body structure used for protection of a crab
The crab's colors indicate the numbers of the crab in the coloring book in which you need to color in order to know what the colors for the flags in the book are.
the pie system
I dont know if this is still useful to you. I just read somehwere that it is simply a white crab spider and that "Crab spiders prefer yellow or white flowers because the female can change to those colors." So sometimes you will see all white spiders, sometimes white with yellow abdomen markings, and sometimes pink because they can change colors.
blue, orange,gray
Colors that crab your attention like pink,green..
Spiders come in a variety of colors. Some like the Crab Spider camoflage.
protect it from predators
some pink crab spiders (Ozyptila praticola) appear grey and pink.
no. colors do not distinguish the gender.