It opens and then closes
All without making a sound.
How cheerful it is all day!
But its voice cannot be found.
Yellow in its center-
Now pick from your palette;
Choose any color in the world
And there is one of me in it.
Now one more hint I give-
You must solve this riddle yet;
Tall or short I may grow-
In the ground I am set.
What am I?

--Kira C., 3rd-6th Grade