Answer:
What goes up and down without moving?
Humans have two that shrink in the light and expand in the dark
Passed from father to son and shared between brothers, its importance is unquestioned though it is used more by others.
Which one of Santa's reindeer can be seen on Valentines day?
I never was but am always to be, and everyone looks forward to me
A mysterious, fantastic creature, It has one defining feature, And for humans at their worst, In their eyes it's just a horse