The sunflower beautiful and useful

Bright, sunny days tend to cheer us up.No wonder then,that people around the world also feel cheered by flower named for the sun-the sunflower!The happy, smiling face of a single sunflower in a garden can lift ones spirit.how much more a big Field full of their bright-yellow faces!........But how do you know how friendly flower came to be so popular? does it really turn toward the sun?and is it truly useful?.