Answer:
Two in a whole and four in a pair. Six in a trio you see. Eight's a quartet but what you must get is the name that fits just one of me.
What breaks when you say its name?
I contain five little items of an everyday sort. You can find all five in a tennis court.
Soft, hairy, from door to door. I am the pet that always stays on the floor. What am I?
You can drop me from the tallest building and I’ll be fine, but if you drop me in water I die. What am I?
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.